The Texas High School gunman taunting his victims. A new toxic danger in hawaii as the volcano pours into the pacific. And diagnosing adhd in kids using brain scans. Tonight the signs doctors say parents should look out for to know when a child should be tested. Announcer this is nbc nightly news with lester holt. Good evening and welcome. We begin with a tense situation thats been unfolding all afternoon long in Baltimore County, maryland. A female Police Officer killed and a neighborhood, the scene of an intense manhunt. Schools were put on virtual lockdown and workers and residents warned to shelter in place. The killing of the officer during an apparent traffic stop brings to 56 the number of Law Enforcement members killed on duty so far this year around the country. Pete williams has late details. Reporter in the air and on the ground, state and local police launched a manhunt in a suburb of baltimore, maryland after a Baltimore County Police Officer was killed. Can you let us know if you can get any vehicle description . Reporter she was dispatched to check out reports of a suspicious vehicle. Police say it appeared that the people in the vehicle had broken into a house. She encountered the suspects and she was critically injured. Our officer was transported to Franklin Square hospital where she was pronounced deceased at 2 50 p. M. Reporter authorities said they were searching for as many as four suspects, men in their teens and 20s. And one apparently got into another car, sped away and jumped out and ran off though initial reports said the officer was shot, witnesses said it appeared she was actually struck by one of the suspects driving away. My son ran in the house stating dad, dad, a jeep just ran over a cop in front of the house. Reporter residents near the shooting scene were urged to stay inside, streets were shut down. Schools in the area delayed afternoon dismissals holding the children inside and told parents to stay away while the search was going on. Baltimore county police havent revealed the name of the officer who was killed. They say she had been on the job nearly four years and is the first woman on that force to die in the line of duty. Lester . All right. Pete williams, thank you. Just in tonight, were getting our first look at a dramatic shootout between police and a gunman on the loose at the president s golf club, the Trump National durall near friday. The pop, pop, pop of gunshots caught on Police Body Cam footage with an alarm blaring in the lobby. Nbcs katy beck has the tape. Reporter the dramatic shootout between police and an intruder at the trump hotel in miami. [ gunshots ] reporter a fire fight captured on Police Body Cam, fire alarms blaring as bullets fly, round after round. The damage visible all over the hotels luxurious lobby as the video shows officers carefully climbing the stairs where suspected gunman 42yearold jonathan oddy was arrested. Police say he scaled a fence at the hotel owned by the president , stole an American Flag and began screaming rhetoric against President Trump and former president obama. Suffering gunshot wounds to the leg he survived and now faces multiple felonies including first degree attempted murder of a Police Officer. Katy beck, nbc news. To the white house now where President Trump today summoned Top Justice Department fbi and intelligence officials. The president demanding an investigation into whether his campaign was infiltrated for political purposes after reports that an fbi informant spoke to a number of Trump Campaign members. Nbc news chief White House Correspondent Halle Jackson has the story. Reporter spotted late today, the Deputy Attorney general walking into the west wing, his agency battling with his boss. The president hereby demand whether or not the fbi or department of justice infiltrated or surveyed the Trump Campaign for political purposes in 2016. It would be very troubling to millions of americans if that took place. Reporter democrats say not so fast. The claim there was embedded in his campaign is nonsense and the country needs to know this is nonsense. Reporter rosenstein under orders to do something, finding a middle ground, expanding an existing internal review, but not starting a new one all together. The white house reiterating what the doj confirmed yesterday, it will ask the Inspector General to look into any irregularities in tactics concerning the Trump Campaign. Rosenstein who oversees the special counsel investigation publicly silent on that today but poking fun at whats become a very visible role. Deputy attorney generals are very low profile, tend not to be recognized. Reporter an fbi informant did speak with several members of the Trump Campaign during 2016, but experts argue it would have been standard procedure to talk to people during the fbi investigation into russian interference. There is nothing wrong with this. In fact, its really the least intrusive means the fbi could have used. Reporter now the president furious and fixated, according to sources familiar with his thinking. Rod rosenstein is in the most difficult position probably in the history of the department of justice. Hes trying to thread the needle between a president who is pressuring against protecting an institution, the department of justice and fbi. Reporter the white house also says chief of staff john kelly will put together a meeting between intelligence officials and some lawmakers to review highly classified materials related to this. Some republicans had been pushing for just this to happen but Law Enforcement officials are hesitant to reveal anything that could compromise a source, lester. Halle jackson, thank you. From santa fe, texas tonight heart wrenching stories of loss and survival only deepen the search for answers following fridays high school massacre. Ten people were killed when a 17yearold student allegedly burst into an art class and opened fire, taunting his victims between trigger pulls. Nbcs Gabe Gutierrez is there. Reporter today outside santa fe high school, a moment of silence for ten lives lost. I could not have asked for a better woman. Reporter william tisdales wife cynthia was a substitute teacher. She had gone back to work two years ago when he was diagnosed with a lung disease. What do you miss about her . She was always there through everything. Weve been through a lot. Reporter inside the school is a trench coat wearing gunman opened fire isabelle and eight other students barricaded themselves in an art supply closet as she says the shooter taunted his victims. What did you hear . He said woohoo. He just screamed it kind of, shouted it. Reporter did he seem like he was everyone enjoying this . Yeah, he was. You could tell he was by the things he was saying. Njoying t . Yeah, he was. You could tell he was by the things he was saying. Reporter in this cell phone video, students run for their lives and you can hear three gunshots. [ gunshots ]. Reporter it was recorded by Susana Salazar who after the shooting learned her younger sister had been shot, thankfully Sarah Salazar survived. Shes strong. We all love her and were all here for her and shes safe now. Reporter shanah fisher had just turned 15 and her mother said she was the First Student killed and had been harassed by the confessed shooter for four months rejecting romantic advances. But today his attorneys visiting their client in jail said he doesnt remember fishers name. They are pouring over his journals to see how long he may have been plotting the attack. I think he seems very confused about the incident and figuring out what exactly happened. Reporter what happened is Cynthia Tisdale left behind seven grandchildren and left behind this note the morning of the massacre. I love you, i hope you feel better today. Love mom. Reporter they had been married almost 47 years. The sheriff says it took officers just four minutes to confront the gunman after the first shots were fired after a gunfight and intense negotiations, he then surrendered about 25 minutes later. Lester . Gabe gutierrez, thank you. Lets turn now to hawaii as we take a look at the angry volcano continuing to explode. This is what it looks like right now. The lava flow on the big island has now reached the ocean for the first time flowing into the pacific and that is now creating a toxic danger in the air. Miguel almaguer is there for us tonight. Reporter exploding to life, kilauea is moving faster, spreading farther, a river of lava pouring into the ocean where magma cascades into the water, laze is formed, acid mixing with shards of volcanic gas, dangerous to breathe. Just like this sulfur dioxide and ash blanketing the air. The ash is foggy, and sulfur and its very hard right now. Reporter with molten fire balls launching into the sky, high velocity lava bomb catapulted into its first victim. Mark classen, rushing to help his neighbor struck in the leg. Dale reporter his friend rushed to the hospital as he stops the home from burning. He had been smashed with about a 12pound rock, has bounced off the railing and obviously hit him were. Reporter with new fissures splitting open, lava is cutting off a highway, and cutting off escape routes, four more homes destroyed and he lost more than his house. We had cats that wouldnt leave so i said goodbye to them and everything else. Reporter tonight a spectacular display of natures power in the air, on the ground and now out at sea. Miguel joins us now. Miguel, i know youre in a safe place but tell me what it feels like to be that close. Reporter lester, you can certainly feel the heat and the power at times the ground here shakes. These geysers of lava are shooting 100 feet into the air, were in a residential neighborhood and a quarter mile away from a geothermal plant and this lava is going into the ocean bringing those toxic airconditions air concerns you talked about earlier. Incredible image. Miguel almaguer, thank you. To the highpowered help joining the fight against our countrys deadly opioid crisis. He took on big tobacco forcing a multi billion Dollar Settlement and now the pharmaceutical industry. Cynthia mcfadden has more on our series one nation overdosed. Reporter attorney mike moore did what even his mom thought was impossible, won a 246 billion judgment against big tobacco. The most historic public achievement in history. Reporter his role in that victory memorialized in the movie the insider in which he played himself, hes putting that experience to work against big pharma charging that opioid manufacturers are largely responsible for the raging epidem epidemic. You called the industry the most corrupt and evil corporate animal in this countrys history. Thats right. Reporter what do you say about big pharma . They are pretty evil. Basically, they did the same thing the Tobacco Companies did, they lied about the addictive nature of the opioids and then went out and marketed these and told doctors everywhere its safe. Its created this huge opioid epidemic. There are 3 million opioid addicts out there in the country right now. Reporter most of whom began with prescriptions. 80 of them. Reporter moore calls out one company in particular for videos like this one. The rate of addiction amongst pain patient whose are treated by doctors is much less than 1 . When you train your work force thousands of sales people to go out and tell doctors that there is less than 1 chance of addiction if you take this drug and you know there is no study that youve done and no reliable study that anybody else has ever done that says that, then of course, youre telling a lie. Of course you are. Reporter purdue told nbc moores assessment is deeply flawed. That oxycontin represents less than 2 of todays opiod prescriptions and its driven by illegal trafficking and abuse of heroin and fentanyl but he and h colleagues recruited 23 states to the cause. You going to win this fight . Im going to win this fight. Im going to keep kicking them until they give up. Reporter cynthia mcfadden, nbc news, new york. Still ahead tonight, diagnosing adhd. The new guidance for concerned parents to catch it and treat it in Young Children. Also, relive the magic and majesty with snapshots from the official Royal Wedding album. Were back now with Important Health news. A potential major leap forward in diagnosing adhd in children. New evidence shows its not just a behavioral condition but a Brain Development problem. Reporter nathan nbcs rehema ellis explains. Was only 3 years old when his mother noticed something wasnt quite right. You really needed to make eye contact with him to get him to listen. Reporter by 5 he was diagnosed with adhd. Adhd is a very real biological condition that is manifested very early on in life. Reporter in fact, as early as 4 years old according to a new study. Researchers complained brain scans of 90 Young Children and found those with adhd symptoms had smaller brain volume, especially in the frontal lobe, the area that controls motor function, attention and decision making. That sounds startling and dramatic to me. Its not subtle, it was throughout the brain. Reporter mark says the study does not recommend more children have brain scans, but it does suggest to have children be tested when they have symptoms like excessive talking and extreme trouble sitting still. We should screen earlier for adhd like other childhood conditions like developmental delay or autism. Im happy we finally figured out what the problem is and how we can treat it. Reporter with therapy and medication, nathan is improving as this discovery shows Early Intervention makes a difference. Rehema ellis, nbc news, baltimore. Coming up, science tries to settle the great breakfast table debate, are eggs good or bad for your heart . And going hollywood, barack and Michelle Obama cut a deal that could make them media moguls. Back with some news to keep in mind for breakfast tomorrow morning. There is a lot of back and forth over the years whether eggs are good or bad because of their cholesterol but a new study claims eating an egg a day may reduce your cardiovascular risk and cut your risk of stroke by 26 . The obamas are coming to netflix. The former first couple is getting into the tv game signing a multiyear deal to make what netflix is calling a diverse mix of content that could include scripted and unscripted series, documentaries or features. Over 29 million americans tuned in, putting on a pot of coffee extra early morning, higher than will and kate got for their wedding in 2011 and here is a view you didnt see. The palace releasing several official portraits including one with a smiling Prince George stealing the show and another with the entire immediate family and finally the happy couple beaming on their big day. When we come back, dead of gratitude, the former bill collector that switched sides to help thousands of people. Inspiring america is up next. Act. But she s doest support it. How republicans in congress are using her name as a weapon in the immigration fight. Plus, the threat an east bay city is making to people sleeping in their vehicles next. The news at 6 starts right now good evening and thanks for finally tonight, its an unfortunate reality that Many Americans are just one Serious Health problem away from a deep financial hole. Collecting unpaid medical debt is a big business in this country, but tonight we have a story of a group turning the tables on debt collections, surprising strangers with a cure for their medical financial burden and they are inspiring america. When a medical emergency strikes, 43 million americans are left with a different kind of trama, crushing financial debt. For three decades, craig antigo was the voice on the end of the line. You were the guy that had to call up and say pay up. In a nutshell, what was your message . Message was this bill, im going to need to have payment. Reporter but now hes using the same expertise that allowed him to collect debt to abolish it instead. What made you want to make a difference and help people . Well, ill tell you, when you go to work and youre having to make 200 calls a day to people that cant afford to pay, it just wears on you. At 5 00 you just want to go home. Now, i cant wait to get up. Reporter antigo and a fellow collector started r. I. P. Medical debt, a nonprofit that uses donations to buy up batches of over due medical bills from hospitals and doctors for just pennies on the dollar. So 100 donation allows the group to wipe out 10,000 in medical bills. They cant respond to individual pleas, they use a formula to find and forgive the neediest, regan adair couldnt keep up payments for migraine treatments. It is aggravating to go out there and see that the bills are in the mailbox. Reporter one day a surprise, a yellow envelope with good news, nearly 3200 of her debt was forgiven. Nobody does good things when nobody is looking. And hes doing that. Hes helping so many people. Reporter rip says they have forgiven more than 120 million in medical debt for more than 60,000 patients. Their ultimate goal 1 billion. You may get this letter out of the blue that says your debt is gone. Thats exactly right. Its a random act of kindness, that you get this letter, or a call from rip medical debt saying your debt is no longer due. Nbc owned tv stations donated 150,000 to the effort and their viewers donated as well. All and all erasing 40 million of debt. That is nightly news for this monday night. Im lester holt, for all of us at nbc news, thank you for watching and good night. Now good evening and thanks for joining us. I m raj mathai. The news at 6 00 starts right now. Thanks for being with us, im raj mathai. Im jessica aguirre. It is being dubbed the libby schaaf act. She is under fire again by an iowa congressman making it illegal to tip off the public about i. C. E. Raids. The act drew the ire of the lawmaker. Reporter were in san jose where many local leaders often express support for undocumented immigrants, but where we have also heard them express mixed feelings about what mayor shaaph did. This new proposal basically bans officials from the purposeful broadcast of information related to any imminent action by a Law Enforcement or agent. It could lead to time in prison. We dont fear these kinds of grandstanding laws. Thats what i call them. Theyre not really laws. These are proposals that will never become laws as far as im concerned. Theyre unconstitutional. And its just political grandstanding. Reporter bob cook calls the proposal appropriate. Some of these criminals are very dangerous individuals. Some of them are gang members. Some beat their wives. Some of them are transporting and selling drugs and a number of other crimes that we dont