tears. "nightly news" begins right now. >> announcer: from nbc news world headquarters in new york, this is "nbc nightly news with lester holt." >> good evening. one question answered, only to raise so many more in the disappearance of malaysia air flight 370. nbc news has confirmed the aircraft piece found on an indian ocean island beach could have only come from a boeing 777. removing virtually any doubt that after almost a year and a half, the first tangible piece of aviation's biggest puzzle has been found. our team is on that island tonight. and here is exactly what experts saw that told them what they needed to know. but what about the rest of the plane, the black boxes? and the passengers and crew. let's begin our coverage from reunion island with chief global correspondent bill neely. bill? >> reporter: good evening, lester. from an island coast that's around 4,000 miles from where mh370 is thought to have crashed. but it's this coast that has now given investigators perhaps their biggest clue yet. more than 500 days into this mystery. the eyes of the aviation world are focused on this debris which investigators are now convinced is the flat of an aircraft wing. which aircraft isn't clear yet. but they now believe a part number 657 bb proves it's from a boeing 777. only one of those is missing, malaysia 370. they are examining the damage and the encrusted shells on the piece that was dragged from the waves by a beach cleanup team. >> it's the first real evidence that there is a possibility that a part of the aircraft may have been found. >> reporter: investigators are also looking at what this man found. the remains of a suitcase nearby on the beach at the same time. origin unknown. for the families of the 239 on board who have endured 16 months of agony, the debris find brings more pain. sara's partner was the only american on board. >> my life has been basically stuck on march 8th, and that's -- i mean -- i can't do that forever. >> reporter: families across the world have waited for any clue for so long. >> the most difficult part is not knowi ining anything. >> reporter: they've been searching day and night for more. in fishing boats, on a coast guard ship and in the air. at first light, a helicopter will resume its search here. ocean experts believe more aircraft debris will be found. this piece will be tested in france soon. significant evidence that might unlock one of the great aviation mysteries. bill neely, nbc news, reunion island. >> reporter: this is tom costello. that new photo of a part number seems to eliminate any doubt about the wreckage on reunion island. sources tell nbc news 657 bb corresponds to a boeing aircraft part listed in the manual as a trailing edge wing flaperon. the flaperon sits on the back of the wing. engineers have already concluded the flap belongs to a 777. this wing flap is in relatively good condition, it appears. what can investigators glean from that? >> they're going to look at the size and the shape of it to see that it potentially could have come apart in flight, or it could have hit the water at a low-impact speed. >> malaysian 370, contact ho chi minh. good night. >> good night, malaysia 370. >> reporter: the last words came on march 8th, 2014, before disappearing on the red-eye to beijing with 239 people on board. radar data showed the plane made a mysterious u-turn. then satellite pings from the plane suggested it flew into the remote southern indian ocean. now the first piece of debris located thousands of miles from the priority search zone off australia, but search coordinators still believe the plane is in that search zone. >> we remain confident that we're going to find the aircraft and therefore be able to locate and retrieve the flight data recorders. >> reporter: oceanographers say the currents in the indian ocean move in a counterclockwise pattern at a very slow rate of speed. so it's not surprising that debris has washed ashore thousands of miles from the search zone. but why isn't there more? >> you have to realize that the debris field by thousand, after 17 months, is probably the size of texas. it's an enormous span, and there isn't very much debris anymore because a lot of it probably has sunken down. >> reporter: french investigators will be looking at that wing flap very closely to see if there's anything suggesting a high speed or a low-speed impact crash or the angle of the crash, any sign of fire or scorch marks. and do the barnacles on the wreckage come from a particular part of the ocean that could help point to the resting place of mh370? the theory has always been that somebody intentionally crashed this plane. lester? >> tom costello, thank you. now to the story that shocked many here at home, a campus police officer going before a judge today in cincinnati to answer for a murder charge after his own body camera showed him fatally shooting an unarmed driver. and now two other officers have been placed on leave in connection with this case. nbc's rehema ellis was in the courtroom. >> reporter: wearing a very different uniform, former university of cincinnati police officer ray tensing entered court with his hands shackled. >> you understand you've been charged with one count of murder and one count of voluntary manslaughter? >> yes, your honor. >> reporter: pleading not guilty in the shooting death of samuel dubose, an unarmed black motorist, pulled over for a missing license plate. bail was set at $1 million. the courtroom erupted. [ applause ] >> ladies and gentlemen, this is a courtroom. >> reporter: tensing a body camera captured the deadly encounter. >> do you have a license on you? >> reporter: after he doesn't produce his license, tensing asked dubose to take off his seat belt. the officer appears to reach for the door. >> go ahead and take your seat belt off. stop. stop! >> reporter: seconds later, he shoots dubose in the head and appears to fall. a second video released today of the body camera of another officer shows tensing on the ground. tensing's attorney says it was self-defense. >> he thought he was going to die. he thought he'd be sucked under that car and run over as he was pulling away from him. >> reporter: the prosecutor's office says it's investigating other officers. today two officers, one of whom supports tensing's claim that he was dragged, replaced on administrative leave. i sat down with dubose's family today. >> in cold bloodshot him for no reason at all. i saw it. i saw it with my eyes. >> reporter: they remember sam as a peaceful man. >> he loved all his kids, and they loved him. they loved him so much. >> reporter: tonight our affiliate station here in cincinnati, wlwt, is reporting that ray tensing posted bond and is out of jail. he's due back in court next month. meanwhile, the investigation into the two other responding officers conditions. lester? >> rehema ellis tonight, thank you. there are fresh evacuations this evening in northern california as dozens of new wildfires flare up overnight, one of them north of napa, exploding to double its size. thousands of firefighters now on the front lines struggling to stop the spread. nbc's joe fryer reports. >> reporter: these are the alarming sights and sounds of this california summer. >> hold up! >> reporter: the orange glow of burning hilltops and the crackle of flames feeding on dehydrated land. >> just flames really, really high and just burning really really fast. >> reporter: in just the past day, more than three dozen new wildfires broke out across the state. triple-digit temperatures and gusty winds are pushing flames in unpredictable directions, burning a few structures. >> it looks like a bomb went off out there. it's devastating. >> reporter: the so-called rocky fire 100 miles north of san francisco is moving quickly, already devouring enough ground to cover 6,000 football fields. >> it became pretty dangerous. some of our crews were in situations where they had to get out pretty quick. >> reporter: at times crews fight fire with fire, intentionally burning dry fuel in the path of the flames. here and across the west, evacuations are becoming a way of life. >> you don't realize what it feels like to be displaced until you are, you know. you just don't have a clue. >> reporter: right now in california alone, nearly 7,000 firefighters are tirelessly battling 14 large wildfires. the back-breaking work takes crews across rocky terrain as they clear away flammable material by hand. they know every inch of parched land holds the potential for sparking the next big fire. joe fryer, nbc news, los angeles. now to an nbc news exclusive that reveals more than anything we've ever seen, just how vulnerable we are in this country to cyber espionage. it shows that according to u.s. intelligence, china alone is responsible for attacks to almost 700 public and private targets in the u.s. in the last five years. we get more tonight from our justice correspondent, pete williams. >> reporter: as the u.s. scrambles to learn the extent of a massive theft of federal government personnel records said to have been stolen by china, nbc news has obtained a classified government report that shows the remarkably pervasive reach of chinese cyber spying nationwide. this national security agency map shows a red dot for every successful computer intrusion by china over the past five years. nearly 700 with computer attacks in every state but north dakota. the northeast corridor from washington to new york is a massive blob of red. and intrusions are clustered around california's silicon valley. the aerospace regions of the pacific northwest, and southern california's defense industrial base. among the trade secrets targeted, the specifications for hybrid cars. formulas for profitable drugs, and the workings of civilian and military air traffic control systems. the fbi says that chinese also target power and telecommunications systems and even some individual u.s. citizens. >> there's no corporate structure out there no matter how small, though, it's a mom-and-pop organization that's immune from this threat. >> reporter: the fbi is now investigating hundreds of cases of suspected chinese espionage, 53% more than just a year ago with estimates that chinese economic espionage cost the american economy $300 billion a year. if there's any good fuse, it's that while the chinese are cyber spying more intensely, the u.s. apparently has the means to know when they do it. pete williams, nbc fuse, washington. coming out of jerusalem today, a knife attack during a gay pride parade. six people stabbed and seriously wounded. police say the attacker is an anti-gay extremist who carried out a similar attack ten years ago and had just been released from prison. planned parenthood is once again under fire tonight. another undercover video has surfaced from activist who criticize the organization's handling of aborted fetuses. it comes as congress readies a vote on stripping planned parenthood of $500 million in government funding which the group says it uses to provide a wide range of services to nearly 3 million people. nbc's hallie jackson has our report. >> reporter: by releasing a fourth undercover video, an anti-abortion group is inflaming a controversy over how planned parenthood donates fetal tissue used for medical research. an official from a colorado clinic describes the public perception of that process. >> and in public i think it makes a lot more sense for it to be in the research vein than, i'd say, business venture. >> reporter: the clinic ultimately chose not to enter into a deal with the activists posing as researchers as planned parenthood insists it's doing nothing wrong. >> we follow the law that says you cannot sell fetal tissue, and we don't. women donate it. there is no selling, and there is no profit. >> reporter: this week its website was hacked as planned parenthood braces for a higher-stakes attack in congress. prompted by the release of the videos, a campaign led by david. is this about a debate over fetal tissue donation, or is this about abortion and doing something to make waves to re-ignite that debate? >> i don't think it's an either/or, and i don't think it has to be either one of those two. this is about documenting and illustrating really clearly for the american people what planned parenthood does to the body parts of the babies that they abort. >> defund planned parenthood. >> reporter: at least 18 congressional republicans are promising to oppose any federal funding of planned parenthood. drawing fire from democrats. >> it's another effort by the republicans to, you know, try to limit the health care options for women. >> reporter: but even supporter hillary clinton called the videos disturbing. the anti-abortion group says eight clips will be released through the fall when analysts say a political showdown could lead to a government shutdown. hallie jackson, nbc news, los angeles. still ahead tonight, a major surge in swimmers getting swept away off american beaches. hundreds every day. we're there for the rescues, the surprising reason behind this blitz. also, that moment on the field that has so many people talking tonight. fans brought to their feet to cheer on a player brought to tears. right now there is an unseen and unprecedented danger in the waters lurking off southern california where a simple swim in the ocean could become a life or death situation in seconds because rip currents are far stronger than usual this season. tonight our jacob rascon takes us along on a mission to save lives. i lifeguard james goldsmith races from one rescue to the next. battling dangerous rip currents plaguing los angeles beaches. suzy beck thought she was drowning. >> we were just diving into the waves, and all of the sudden looked up and realized we were so far out. >> her boyfriend jonathan never imagined he would be that guy. >> i sat on the shore a lot of times and made fun of people that had to get rescued. i guess i can say it's my day. >> they're rescued by the hundreds every day, more than 1300 in the last five days. at venice beach, 18 people were caught in a fast-moving current at once, loaded on to two baywatch rescue boats, what lifeguards call a blitz. >> you can be in knee-deep water and the waves come in and lifts you off the bottom. and within seconds you're 50 feet offshore. >> reporter: lifeguards are performing more rescues than ever, partly because these beaches are busier than ever. expecting roughly 3 million people this weekend alone. meteorologists blame monster storms in the southern hemisphere for creating larger than normal waves, and the more intense currents. in ten minutes, we watch four people get rescued, including two children. >> they're swimming in. but the rip current is pulling them out as fast as they're going in. so they're not making any progress. >> reporter: at this rate, l.a. county lifeguards will easily set a record, saving more than 16,000 swimmers in a year. a day at the beach now more dangerous than ever. jacob rascon, nbc news, venice beach, california. up next, the u.s. government now says it's looking for the dentist under fire for the killing of that beloved lion. but where is he? the feds tonight are trying to track down the american dentist at the center of an international outrage. he has remained out of sight since the world learned he killed a cherished lion in africa. a death that has raised some bigger issues now. we get more from our kevin tibbles. >> reporter: the outrage over cecil's killing has triggered a worldwide petition. more than 800,000 signatures calling on zimbabwe to put an end to trophy hunting. still no sign today of walter palmer, the minneapolis dentist and big game hunter responsible for cecil's death. he has said he'll cooperate with authorities, but today the u.s. fish and wildlife service investigating the incident said multiple efforts to contact dr. walter palmer have been unsuccessful. hunting isn't the only human activity to threaten many animals, nor is it the biggest. conservationists also point to loss of habitat and poaching. two species of rhinos are critically endangered. more than 1200 were killed last year. african elephants are in dramatic decline, down 64% in the last decade. poachers kill an estimated 100 elephants each day. some say legitimate hunters are getting a bad rap. >> the hunting community pays for most of the wildlife conservation worldwide, and particularly in africa in these very sophisticated programs that are designed to save the lion. >> reporter: but there is no doubt that cecil's death has touched a nerve. >> to know that something as powerful and symbolic as cecil can die so treacherously and so tragically, it just shows what a slippery slope we are when it comes to protecting the rest of africa's amazing species of wildlife. >> reporter: kevin tibbles, nbc news, minneapolis. a thumbs-up tonight from former president george h.w. bush. his camp tweeting a photo of 41 in a brace on the mend after falling and breaking a bone in his neck. we wish him well. and we want you to know tomorrow i'll be speaking with jeb bush about his run for the white house. we'll have that for you right here tomorrow night. still ahead on "nightly news," a ballplayer's heartbreak. why he was reduced to tears in the middle of a game. burning right now, in the delta -- near antioch. ===janelle/take vo=== then: criminals increasingly cashing in... in san jose. the crime a shrinking police force can't seem to stop. ===next close=== the news is next. are you crying? there's no crying. there's no crying in baseball. >> we love tom hanks, but it turns out there is crying in baseball, as we saw on the field last night here in new york. it was all because of a rumor that spread on social media, and then throughout the stadium, leaving a major league player in tears. nbc's harry smith with what happened. >> reporter: wilmer flores has been having a tough year. to say he is error prone is an exercise in restraint. but it's not been all bad. >> near the wall, it's out of here! wilmer flores with a grand slam. >> reporter: yet last night at citi field, flores was in tears, emotionally overcome. >> this is a business part of the game, gary, and it can be heartless. >> reporter: during the game, social media lit up with reports the kid was being traded. somehow he found out. was he humiliated or heartbroken? >> everybody in the ballpark thinks he's traded but him. because i hadn't said anything to him. how would you react? >> reporter: his manager said he didn't even know. >> somebody came to me and said wilmer is crying. i said, why? well, he got traded. to who? for what? i didn't know. >> reporter: and this being a story about the mets, the required twist is the trade fell through. >> i was sad, you know, being a mets forever. and all my teammates here. that's why i got emotional. >> reporter: flores, who signed with the mets when he was just 16, wanted to be a met for life. now that he still has his job, he'll have a little time to rethink that. harry smith, nbc news, new york. >> that will do it for us on this thursday night. i'm lester holt. for all of us at nbc news, thank you for watching and good night. a devastating sighte live pictures from our nbc choppfl a devastating sight tonight. live pictures from our nbc helicopter. flames tearing through a mobile home park in the community of isleton. that's in the delta off highway 12 near rio vista. several mobile homes have been leveled. thanks for joining us. i'm janelle wang in for jessica aguirre. >> i'm raj mathai. difficult to watch those homes go up in smoke and flames. this mobile home park has been evacuated. the owner of the park tells us everyone who lives there was able to get out safely. sos that very good news here. but we continue to look at these live pictures of the firefight and the homes. several homes already have been destroyed. others damaged. no official count quite yet on the extent of this damage. but you can see it in front of your eyes. it's in the heart of the delta, near isleton. technically it's in sacramento county. but the solano county fire department is the lead agency. it began as a grass fire around 4:15 and the fire spread to these mobile homes. there's also boats on the property and some cars. this is video from about 30 minutes ago as the flames roared, sending thick smoke into the air. let's check in with our chief meteorologist jeff ranieri. during the 5:00 newscast, we were watching this and seeing the smoke and the wind direction really playing havoc for the firefighters. >> that's the biggest thing, this wind is not going to let up.