now, an afghan refugee says he feels like a human being for the first time in his life after arriving in the uk with 28 others from the lgbtqi plus community. the man who the bbc is not naming for safety reasons fled afghanistan after the taliban took control of the country in august. the relative safety in goanna hz country in august. the relative safety in goannahz and's gay community was wiped away. for security reasons, his words are spoken by an actor. translation: we travelled on a royal air force aircraft| and i cannot express my emotions. i feel blessed and i'm so excited. i am free. when we arrived in the uk, the people who greeted us were so friendly and welcomed us warmly. i was surprised by that much kindness. i asked myself why people on this side of the world are so friendly towards us. for the first time in my life, ifelt i was a human being. everything collapsed after the fall of kabul. the freedom of people, and especially the lgbti community had previously, has been demolished. we were so scared. as you might know, this community was a secret underground community but we knew each other and our network, and if one of us got arrested, they could have found the rest of us. kabul is not a big city and with the way the taliban is ruling the country, it was not that difficult to find high profile lbgti people. we also heard a couple of people were arrested and were so scared. like many other gay men in afghanistan, we lead a double life. i have a wife and kids. if i was arrested, you can imagine it would be a nightmare for me, and especially in front of my family. i tried so hard to leave the country i also tried so hard to hide the reason for my departure from my family and got in touch with a couple of international lbgti organisations, and thankfully they acted fast. britain is a new home for me. everything is new to me here. a new lifestyle, a new language and culture, i'm nervous about my future and i'm trying to figure out where to start my new life, but man, i feel safe and free. this is amazing. now on bbc news, our world investigates the controversial technology that could help tackle america's growing gun crime problem. operator: 911, - state your emergency. man: itjust sounded like there were fires of gunshots. - how many shots? 15 or 16. on average in america, 50 people are killed every day with guns. do you feel safe here? no. in california, we have the worst gun violence. it's just terrible, man! 0ne company, shotspotter, says its gunfire locator technology can help tackle this huge problem. shotspotter is the reason why we were able to apprehend him and stop that killing spree. but some have questioned how often the company gets it right. so, is that like a typical type of call out from shotspotter? yeah, we look, don't find anything, can't find any evidence. and when things go wrong, what are the consequences? to be injail and not know what you're there for, emotionally, you're a wreck. does this technology work as well as the company claims? and what role can it play in the american fight against gun crime? you can tell a lot from a waveform. how loud, how high, what frequency. train a computer algorithm and it can, in theory, work out what it might be listening to. the's the idea behind shotspotter — that a computer can detect a gunshot and then tell the police the location it was fired from. gun fire. small mics are placed around a neighbourhood. when a gunshot is fired the mics pick up the sound, how long it took to reach the sensors and from which direction, effectively triangulating the shot. shotspotter was founded on the west coast of america in the mid—90s, in that cradle of american innovation, silicon valley. the company has agreed to give the bbc access to show me how the system works and why they believe it's needed. what makes the system so compelling, we believe, is the fact that in many communities that suffer from ongoing persistent gunfire, people for a lot of reasons don't call 911 which means there's no police response which means that communities begin to distrust police. you can see we've got some proximal incidents right here. this is shotspotter�*s incident review centre. ginger is one of the analysts. wavy alarm sounds. 0h, there's an incident right there. that's the sound we hear when an incident comes up, yep. when the computer thinks a gunshot has been fired, herjob is to review it and decide whether to dispatch police officers, all in under 60 seconds. this is a waveform which if you do any kind of audio work, you've seen this before. so we're listening to that, we're looking how far does the sound travel, we're looking to seeli how many sensors picked it up, if the sensor has made a directional pattern because, in theory, a gunshot can only travel in one direction. to me it doesn't look like it's gunfire, but that's why we also listen to it. wavy alarm sounds. possible gunfire pops. that sounds like gunfire to me. in this case, i think you might be right — we've got a directional sensor pattern. i'm going to call it gunfire. i'm going to submit it and i'm going to send it over to our agency, and you can look up there, itjust popped up right now. so now, it was that quickly, there's going to be police going to that location right now? correct. the people in this tiny room are listening to cities across america, there are over 100 of them, and their decisions what is a gunshot and what isn't a gunshot is absolutely crucial. it could be the difference between life and death, between finding a criminal and not. i'm travelling to fresno because i've been told of a shooting incident which proves shotspotter�*s effectiveness. in 2017, kori ali muhammad was on the run, wanted for murder. he had a hatred of white people and on the 18th of april he decided he wanted to shoot as many white men as he could. operator: 911, - state your emergency. man: itjust sounded like there were fires of gunshots. - how many shots? 15 or 16. fresno police officer bill dooley describes what happens next. he comes up to the passenger side where the first victim is and lifts up his weapon and fires four shots and kills our first victim. operator: 911, - state your emergency. man cavme: my i partner's been shot! this is when our very first shotspotter activation comes out. although there were plenty of 911 calls, they were delayed and unspecific. shotspotter, however, was alerting police to his route, one shot at a time. he starts heading west on mildreda, he sees a gentleman coming out of his house on the south side of the street so he fires two shots, misses the individual who came out of his house... gun shots. he continues to travel down towards fulton and that's where he sees his next victim. so he's fired his first two, he's running up to the victim who now is down on the ground. gun shots. he fires his next two shots. muhammad then runs towards a group at a bus stop and chases an older white man towards a car park as he reloads. and that's where we have our last shotspotter activation. gun shots. operator: 911, do - you have an emergency? woman: yes, there's a guy out here that's bleeding, _ he got shot. ok so the suspect, do you know where the suspect is? he's runnin' around out here. three people were killed in the space of 90 seconds that day. police identified where muhammad was going and arrested him as he headed towards busy downtown fresno. shotspotter gave us the clear path that he was taking. because of all the 911 calls that are coming in, information is good but it may not be up—to—date. the up—to—date information was shotspotter. so for you shotspotter in this scenario was essential. 0h, absolutely. there's no doubt in any of our minds that additional lives would have been at risk or lost if we had not apprehended him as quickly as we did. shotspotter is the reason why we were able to apprehend him and stop that killing spree. there are clearly examples of shotspotter system working, even saving lives. and for years it's been used by police forces pretty uncontroversially. that was �*till lawyers around the country started to ask questions, difficult questions about how the tech actually works. they started wondering whether it's as accurate as the company claims, and if it isn't, what the consequences are for americanjustice, and those questions have been loudest here in the city of chicago. so talk me through, where are these actual shotspotter sensors here? you see the round ball thing, the black thing at the very top, that's the centre up there. how do you feel when you see them? it makes me angry. michael williams was released from jail two months ago, having been accused of murder. 0n the 31st of may last year, michael decided to take a drive to buy some cigarettes. it was a night of protests over george floyd's murder. there was crowds of people, they was all over the place. that's what made turn around. someone he recognised from his neighbourhood asked him for a ride back home. he agreed. i stopped at this light. he wasn't even in the car two minutes before another car pulled up and opened fire, struck him in the head, and i was hollering out to my passenger, you "are you all right right, you 0k, are you hit?" and he wasn't saying anything and when i glanced up at him from the floor i saw the blood coming down and ijust put the pedal all the way to the floor. michael took the man to hospital where he later died from his wounds. two months later, the police knocked on his door. he was arrested for first degree murder, accused of shooting his passenger in his car. brendan max, michael's lawyer, talks through the case against him. the police had no witness who said that they saw michael shoot anyone. they had no weapon, they had very little evidence in this case other than a shotspotter alert which directly led to him been charged and incarcerated in this case. we had two reports from shotspotter. one was signed by one of their expert witnesses. the shotspotter alert placed the gun shot around the location of michael's car. it was used as evidence in a case against him. to be in a four corner concrete room for 11 months... ..with 39 other people, and you know you haven't done anything. it does a great deal to you, mentally. ijust couldn't function like a normal human being. it got so bad for me in there, i was on several medications. ijust saved them up, i was hoping that it would have put me into a deep enough sleep to stop me from breathing. while michael considered taking his own life, fortunately, he didn't go through with it. after 11 months injail, and despite shotspotter giving the police a detailed forensic report, or dfr, attesting to the location of the gunshots, the prosecution suddenly withdrew their evidence. the case was dropped. it is well—known on a dfr and also our standard contracts that we don't warrant or stipulate to detecting what's called suppressed gunfire, and suppressed gunfire are gunfire that happens indoors or a gunfire incident that happens in a park. it became very clear at some point in time that with that explanation or that description of what we can warrant to and what we would testify to, that was in conflict with the prosecutor's theory of the case. spotspotter evidence withdrawn, charges dropped. brendan max, however, doesn't buy that response. we showed him shotspotter�*s explanation. ..suppressed gunfire are gunfire that happens indoors or... what mr clarkjust said is two things. there was a gunshot here, so shotspotter worked correctly. mr herring was shot, so our report was right. and on the other hand, he's saying don't trust our report because the shot may have come from inside a vehicle under one potential theory of this case. those things are contradictory. brendan max found something else — that the algorithm had initially classified the gunshots in michael williams' case as a firecracker, but a human had reclassified it as a gunshot. however, that detail was not in the forensic report shotspotter gave to the police. and in fact, when i visited shotspotter, the algorithm disagreeing with the human analyst was fairly common. this one is probable gunfire. popping sound. i think it's a firecracker. we are not under no obligation to go with what it tells us. it will suggest, but we're looking at so many other things in such a short period of time. honestly, i don't even look — i am so busy looking at the sensor patterns. like, all of the sensors got skipped. i don't think it is anything. and you can hear there's the little pulse and then there's the big pulse right here. popping sound. i think it is a firecracker so i'm gonna go ahead and dismiss it as such. during the process of defending michael williams, brendan max began to suspect something. shotspotter claims their system is 97% accurate. brendan max began to wonder was that really true? police radio chatter. i want to see how shotspotter is used on the ground and fresno police have invited me along on a night patrol. i'm out with 0fficer palomino. popping sound. so that was the activation. oh, that was it right there? yeah. radio: shots fired. came in at 2252, about four minutes ago, so our helicopter is above the address that the spotspotter pinged at. we went to the location where shotspotter had detected a gunshot. so we think there were shots fired on the street somewhere? yeah, that's where the shotspotter activation was pinpointing it. this is where it was — this is where the shotspotter was indicating. so it's literally underneath this tree where it thought the shots that happened? yeah, that's what they said. so you have had a look for casings. mmm—hmm. have not found any. right. what — do you think there was a gunshot here? i mean, you can't really say, but if there is no evidence of a gunshot or... so was that like a typical type of call—out from shotspotter? yeah, that's pretty normal. yeah. yeah, interesting. we look, don't find anything, don't get any — can't find any evidence. no house is struck, no vehicle struck, no other callers. the police tell me this kind of scenario is common. when a shotspotter alert is created, it's often hard to know when a gunshot has actually been fired on the ground. that makes trying to work out how effective shotspotter is tricky. we wanted to really get at the question of the operational value of shotspotter, so we looked at about 50,000 shotspotter alerts over a period of 1.5 years and we found that in only about 9% of those shotspotter alert responses does the police department record having developed some evidence of a gun—related crime. did that surprise you? well, a 9% success rate in developing evidence of a gun crime does not look to me like an operational value that necessary outweighs the cost and the risks of the use of shotspotter. the inspector general of chicago said that they believe only 9% of dispatches there is any evidence of an actual gun crime or even a gunshot. how do you respond to that? i've read this report a few times and what they are stating is that there is a 9% reported evidence of something being found. right. it does not mean that there wasn't evidence found. but that leads to the next kind of obvious follow—up question — if it's so difficult to work out whether a shot has actually been fired on the ground, how does shotspotter know with such confidence that it's 97% accurate? on our ride along, i saw for myself. popping sound. shotspotter says this figure is accurate because the police officers themselves are able to listen to the noise recording and feed this back to them — something they call ground truth. and that's part of the feedback that you are basing that figure on? absolutely — yeah, that is the feedback. we rely on ground truth from agencies to tell us when we miss, when we miss detections or when we misclassify. other people have said about the general stat of 97% stat that it is not rooted in scientific rigour — i.e., it has not been scrutinised, it hasn't been peer reviewed. do you think that is fair? it is so certainly a factor that there has not been an academic peer review of the service, but i would push back in saying that it is not been analysed — it has been analysed for 20 years across 100—plus customers that are using it every single day. here's the problem with that — often, it's pretty hard to tell whether a gunshot has been fired by simply listening to the audio. so it's actually pretty difficult to know whether there was a gunshot or not. hmm—mm, yeah. i mean, it definitely could have been and it'sjust we don't have anything to prove that it was, so we just clear up the call and that's pretty much it. right, just from listening to it, did you think it was? yeah, it sounded like a gunshot. yeah? sounded like it, but who knows for sure. right, and also, you are not an acoustic expert. yeah, exactly. ..analysed for 20 years across 100—plus customers that are using it every single day. what mr clark had to talk i about there was marketing, it was not science, and to hear the ceo of this corporation say that that is the basis - for the claims they've made for many years, for— the evidence that has been used not only against michael but against hundreds . of defendants around - the country, it's outrageous. all chant: i can't breathe! following the death of george floyd in may last year, the use of shotspotter became even more controversial as trust in the police was at an all—time low. we need to steer them away from technology and to the people. in chicago, activists argue the tech is disproportionately deployed in black and brown communities, so could be dispatching police to neighbourhoods where they think a gunshot has been fired, guns drawn, when, in fact, there has not been. like, we might not get the answers that we want. alyxandra is overseeing today's meeting and wants chicago's shotspotter contract to be cancelled. it's sending police in to, like, these situations that they expect to be hostile, they expect there to be a gun. because, again, of like, where this is deployed, they are expecting a black or latinx person to be holding the gun. people are being stopped and frisked, harassed by police, stopped by police because they happen to be in an area where shotspotter is actually deployed and where the alerts are actually going off. why are we paying millions of dollars for something that sometimes works? people almost want to say well, if the real problem would be officers showing up trigger—happy, that is something we immediately do a dfr on. we have to do a dfr on that, because those are really big things. we don't see that. we we — don't see that. it's not in the data. it'sjust not in the data. police across the country do believe shotspotter is effective. fresno is looking to expand shotspotter into other areas. this expansion is going to be close to a million dollars a year the city of fresno is paying for this service. it's got to be worth it. it's gotta be worth the money. and if we ever find out it's not worth the money or it's inaccurate or it's actually hurting our efforts instead of helping our efforts, then i'm going to look into getting rid of it. but right now, it is proving to be very useful. on our ride along, we came across a group in an area that did not have shotspotter. do you know where the gunshots were coming from? it sounded like by the orchards. theyjust heard shots being fired. do you feel safe here? no! in california, we have the worst gun violence. i hear every single day there is another article about someone getting shot. it's just terrible, man! let me tell you something, bro. most of the problems out here in fresno are due to the manpower that the fresno police department has. you know, they can't have one crew here and two crews over there. so you want more police? well, yeah! yeah, i honestly do! clearly, there are people that feel unsafe in their own neighbourhoods for whom shotspotter could be a welcome piece of technology. and yet, if it is not so accurate, this could have huge knock—on effects for the criminaljustice system. in the last four or five months, i'm aware of dozens of chicagoans who have been arrested based on shotspotter evidence. i'm sure that has played out in cities across the country. shotspotter needs to be dismantled because it's doing more damage to us than anything. i mean, many of us is gonna end up in the countyjail? but shotspotter can get police officers to gunshots more quickly. the technology does save lives. what if shotspotter only saves one life in a given year? is it worth $1 million? in our view, it is, because you cannot put a price tag on the human life. ultimately, though, until shotspotter�*s reliability has been independently established, there will continue to be questions about whether this surveillance technology should be used so widely. good morning. saturday started off very wet for some of us but the story quickly improved to some sunny spells in the afternoon and just some isolated showers and areas have seen some pretty miserable weather recently including the borders, well, it was better today with glimpses of sunshine around. similar story today. sunday will start off pretty wet across some areas with a significant area of low pressure and into the southern flank of that low we are likely to see gale—force winds and that may act as a friend in some respects. it will push the heavy early morning rain quickly northwards and it will tend to linger across the far north of scotland but an improvement as we go through the morning and into the afternoon with a frequent cluster of showers driven in along west—facing coasts. gusts of winds inland close to 30mph, but those west facing coasts, possibly 50mph at times. in terms of the feel of the weather, 10—13 degrees in scotland and northern ireland, 13 or 1a further south. moving out of sunday into start of monday and the start of a new month, the low pressure will drift off into scandinavia and the wind direction will swing north—westerly, a cooler source, and that will drive the warmer yellow tones back to the continent, the cooler air mass pushing across the uk, meaning temperatures in the first few days of november could bejust a little bit under par for this time of year. we start off monday on a chilly note first thing where we have clearer skies and a frequent rash of showers driven along by the brisk north—westerly wind, some showers pushed further south as we go through the afternoon. temperatures just 8—10 degrees into the north and may be a maximum of 12 or 13 further south. the middle part of the week, that north—westerly flow is likely to stay with us and we see the ridge of high pressure trying to build in from the atlantic, and it is likely to kill off some of the showers but it does mean that we are going to stay on the cool side for this time of year. it also means we could see more in the way of overnight frost and we have not seen much significant frost so far this season but it means that overall things will stay dry and quieter but on the cool side as we go through the week ahead. take care. hello, you're watching bbc news. i'm rich preston. our top stories: covid, climate change and iran. pressing issues being hammered out by world leaders at the g20 summit in rome. three people are killed in sudan as thousands take to the streets to protest against the military coup. 80's against the military coup. health system is on the verge 80's health system is on the verge of collapse with gangs holding the country's fuel supply hostage —— haiti. and voting gets under way injapan. the governing liberal—democratic party hoping to maintain its grip on power. and feeling frightful? 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