>> having been accused of a crime i didn't commit? >> and batter up? >> sports illustrated's latest cover girl went into the little league series undefeated tonight. but only one team can make it to the u.s. championship. but first. the "nightline" five. good evening, tonight, the global manhunt is on for the world's most wanted men, the islamic terrorist responsible for executing american journalist, james foley, just hours ago, the fbi director claimed the full force of the agency will be brought to bear on the terrible, senseless killing. but who are the jihadists spilling hate with an english accent? more on our series "nightline" investigating. >> reporter: as outrage spread around tell world today over this scene, jim foley's brokenhearted parents said they had never been prouder of their son. >> he was strong, courageous, loving to the end, i mean, we just hardly recognize our little boy. i mean, he was just a hero. >> and you know from the videos that his last words were, i wish i had more time -- to see my family. >> reporter: as foley's family mourns their loss, president obama called for the world to finally stand up to the threat of the brutal isis group. >> no just god would stand for what they do every single day. >> reporter: the u.s. was looking for clues on the identity of the hooded executioner of jim foley, using a data base to look for his eyes, hands, and most telling his voice with what british authorities call a distinctive london accent. >> and go far out of the way to find reasons. >> from what we see it looks increasingly likely that it is a british citizen. this is deeply shocking, but we know that far too many british citizens have traveled to iraq and syria and take part in the extremism and violence. >> reporter: in the last year, foreign fighters from britain, elsewhere and the u.s. have helped isis conduct a well-funded, well-armed brutal holy war. seizing large areas of syria and iraq where christians and non-believers have been executed, some beheaded and even killed. in some ways they are even more extreme than al-qaeda. >> if somebody says oh, it is a long way. there is no threat to us. it is a threat, they are dangerous and after us. >> reporter: especially with so many western recruits, many from the streets of london. >> what is it you hope to achieve tonight. >> reporter: it is a place that was reported earlier this year, young muslims conducted sharia patrols to enforce stricter sharia law. >> a bad thing, a noble aim. but sharia, sadly, i think that will be the beginning of the end of the united states of america or britain and europe. and taiwan is currently being governed by man made laws. >> reporter: and over the last few months a growing number of british recruits have appeared in isis propaganda videos. >> to all of my brothers living in the west, i know how you feel, in your hearts, you feel depressed. come to jihad and feel what we are feeling. >> reporter: james foley learned that firsthand, a former hostage was held with foley in a dark cell for some several months told abc news that foley was often singled out for tough punishment, once for planning an escape. >> james, for being an american, and if he kept to his fundamentals that he had, and a brother serving in the u.s. air force got unfortunately a bit of a special treatment. he was kind of a scapegoat. so every time they would be around, the kicks and punches, he would get a bit more than the others typically. >> reporter: but anan also said that foley was never afraid even in the darkest hours. >> he was always very strong. and i -- i could see that he -- he gave luck to lots of prisoners. every time we had a setback he was telling us, oh, don't worry, mate. >> reporter: there was no further word today about the other american hostage shown on the video. steven sotloff, who isis also threatened to kill if the bombing in iraq continued. president obama said the u.s. would not be intimidated. >> we will be vigilant and relentless, when people harm americans everywhere we do everything we can to see that justice is done. >> the battle for the country's largest city is also taking a deadly toll on citizens. >> reporter: foley filed his report from his global post just before he was captured almost two years ago. >> this location in aleppo, james foley for global post. >> reporter: in his final moments, james foley faced death with a courage that marked his journalistic career. and tonight, details if they had worked would have saved his life. senior officials tell abc news that president obama authorized a bold, u.s. military operation into syria earlier this summer to rescue foley and several other u.s. hostages. but then when the special operations attempt arrived at the site there were no hostages at the site. officials say several u.s. forces were involved and several isis fighters were killed. there were no other casualties, and why the intelligence was not good enough. >> i know we'll continue to report on that. as always, thanks, brian ross for your extensive reporting. and next up, the shocking investigation into the arson squad once known as america's best. r rheumatologist about a biologic... this is humira. this is humira helping to relieve my pain and protect my joints from further damage. doctors have been prescribing humira for ten years. humira works by targeting and helping to block a specific source of inflammation that contributes to ra symptoms. it's proven to help relieve pain and stop further joint damage in many adults. humira can lower your ability to fight infections, including tuberculosis. serious, sometimes fatal infections and cancers, including lymphoma, have happened, as have blood, liver, and nervous system problems, serious allergic reactions, and new or worsening heart failure. before treatment, get tested for tb. tell your doctor if you've been to areas where certain fungal infections are common, and if you've had tb, hepatitis b, are 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there we take over. >> reporter: this is captain sam richardson. >> it is too far today. >> reporter: they are investigators with the phoenix fire department's elite arson squad. the best of the best. and they have the numbers to prove it. the squad solved more cases in the arson unit than anywhere in the country. >> we can go into a structure and be able to start anywhere. to a lay person they just look at you like how do you know that? >> reporter: but did that success come at a price? >> i was going to prison for the rest of my life for a crime i didn't commit. >> reporter: tonight, two people who say they were falsely accused of arson, alleging incompetent actions. you were in jail for 16 months? >> it ruined my life and i'm still paying for it to this very day. >> reporter: but our story begins in 2009. abc news was given extraordinary access to this elite unit. so we could see for ourselves what made them the best in the nation. captain andes was proud to admit he had a secret weapon. >> this is a detection k-9. >> reporter: she is commonly used in arsons, highly trained. but there was another force at work, the unit's new controversial director, jack ballantine, a highly decorated police detective. >> my job is to make sure that they can realize success on every one of the cases that they go on. >> reporter: between ballantine's leadership and sadie's nose, the clearance rate went up. but the record was about to be called into question. >> phoenix 911, where is the emergency? >> there is a fire -- >> hold on, i'll put you through to the fire department. >> reporter: may 13th, 2009, the home of barbara slade was on fire. >> this is the back of the house, you can see we had a pretty good fire here. >> reporter: in this video filmed by richardson, tell tale signs of arson around the house. >> the glass was around the drier, the iron plugged in. >> reporter: there was a dete detectdetec detected accelerant around the house, but one problem, barbara sloan says she didn't do it. are you an arsonist? >> no, i was being framed for a crime i didn't commit. >> reporter: sloan was charged with arson and faced 29 years in prison. >> i sat down with my family and prepared my son and my daughter that their mom is going to jail for the rest of her life. >> reporter: for her defense, sloan enlisted a certified fire investigator with 30 years of experience. when you first looked at the evidence, what was your reaction? >> overwhelming, it was clearly a fire that started in the garage. >> there is a fire in the garage. >> the garage is completely engulfed. >> reporter: he says all the physical evidence pointed to one of sloan's cñ-rs. a toyota corolla model that had been recalled for defects, including cracks that he believes sparked an electrical fire which then spread throughout the house. >> sam richardson never even entered the garage. >> so you think this was fire investigation 101. >> this was below fire investigation 101. this is kindergarten fire investigation. >> reporter: but the sloan case is not the only one. >> building on fire. >> reporter: just six days prior, richardson and andes were called to another fire, richardson made up his mind on the scene. >> so this will be an arson fire, with a possible suspect. >> reporter: the suspect was a former sheriff's deputy in the house, he was behind on his rent and had been fighting with his roommate. >> he had not been paying his rent, they were fighting, he came back and got mad. i saw him prior to the fire. >> reporter: part of the suspicion was you were trying to kill your roommate. >> correct. >> reporter: any truth at all to that? >> none of that. >> reporter: richardson took on the role of interrogator. >> i got three points, somebody poured this. the dog is hitting everywhere. >> reporter: sadieaccelerants as enough to arrest capos and keep him in lock-up for six months. but then the case fell apart. the parts that they said sadie alerted to? no evidence. the prosecutors dropped the charges. and back in the sloan case turns out the same thing happened. sadie found accelerants that the lab did not. why did sadie get it wrong both times? listen to the possible reason why. there is a stunning comment that is made. >> please fake it for me, okay? >> fake it. those words were unbelievable. i could not believe what i was hearing in his tone of voice. it was not just a joke. >> better? show me. >> i was shocked. i don't understand why fred andes did that. said he hit on the dining room. she also hit in the kitchen area right by the stove for it looks like the presence of igniteable liquid. >> reporter: prosecutors dropped the case against sloan, in the deposition, captain richardson admits he made up his mind before he had all the facts. >> i knew when i left that day this was an arson. >> before you got any lab support back, right? >> yes. >> reporter: then it was captain andes' turn, he was grilled about the statistics. >> do you keep those statistics? >> no. >> why not? >> i believe she is far superior to what the labs can do. >> you have no idea how accurate? 99% of the time. >> how does this strike you? >> it is absurd to think that a 6-year-old lab is smarter than an individual that has a college degree in chemistry. >> reporter: it is true, arson dogs often find trace amounts of accelerants that can't be confirmed by labs. that is because they're detecting trace elements too small to be meaningful. too small to start a fire. so according to the national fire protection agency sadie's alerts should never have been used to indict sloan or capos, we wanted to interview him but he declined an interview citing the investigation by the phoenix department of public safety launched earlier this year. when we showed up at his house he didn't have much to say. >> i can't talk about the investigation. >> reporter: actually we talked to the investigators -- >> the person i can't trust is the media. >> reporter: sir, why is that do you think? but andes did tell us something back in 2010, something in hindsight that could tell us a lot. >> we used to think we have to have concrete evidence, and now we can put a case together with circumstantial evidence and make it stick, time and time again. >> reporter: his boss declined an interview as well, citing internal investigation. when we caught up with him? good morning, fire marshal, byron pits from abc news, can we talk to you about the investigation? i take it the answer is no. >> reporter: just last month, the results of the investigation were finally released. the department of public safety recommended charging richardson with six counts of false swearing and andes with one, all felony counts in arizona, no charges against ballantine were recommended. although all were placed on assignment. up next for us, show me the mo'ne, the littlest thing to has been in baseball throws down at the little league series tonight. abc news "nightline." brought to you by nexium 24 hours. s 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faces the undefeated team in the little league series. >> another shot for mo'ne davis. >> reporter: she has the arms. and the power. >> that went back up the middle. >> reporter: and the attitude. >> follow my curve ball, like clayton kershaw, and my fastball like mo'ne davis. >> reporter: her mad skills making her famous, now the first boy or girl to hit the cover of sports illustrated. the team's not so secret weapon with the fastball clocking in at 70 miles an hour, leading her team to the little league world series. and after a two-hit shutout last friday? the first ever in a little league world series, she was on the mound again tonight. >> strikeout number six for mo'ne davis. >> reporter: but she was moved to the outfield in the third inning to spare her arms. her opponents proved powerful, too. >> he rips this one in the corner and left. >> reporter: holding onto an early game lead, and ultimately winning, 8-1. >> and it's over. >> but hang tight, mo'ne's team will play again tonight on our partner network. tune into good morning america tomorrow, and as always we're on line at abcnews.com. good night, america. come on, ray. where are you going? i told you yesterday i was going to pick out paint colors for the bedroom today. i told you i wanted to go golfing. yeah, and i said, "too bad." i thought that meant for you. ray, i'm going to the hardware store. you only have to watch the boys 'cause ally's at molly's. i'll spend the whole day with them tomorrow, i promise. i'll even-- i'll skip church, okay? i'll give my kids the time i normally reserve for the lord. do you want to be any part of their childhood memories? "childhood memories." come on. ask them about their trip to disney world. they don't even remember it. they were three. tiger woods could hit a ball 200 yards when he was three. okay, ray. gahead, you go golfing. i'll drag them around with me all day. i'm sure thell have a wonderful time looking at paint samples. there you go. yoput those golf clubs down, spend some time with your kids, and create some damn memories! all right! maybe you should worry about the memories