Urging a new strategy on health care. Plus why Vladimir Putin is kicking out more than 700 american diplomats from russia. Tourists targeted. The law professor shot while with his family at an island resort. The Security Guard tied up, the is this dream destination turning dangerous . This is abc world news tonight. Thanks for joining us this sunday. Im tom llamas. We begin tonight with chilling new developments in an alleged terror plot. Police conducting raids across sydney, arresting four men they say wanted to take down a commercial airplane with an improvised device that may have used toxic gas. Security stepped up at airport terminals across the country. Authorities there probing reports the suspect may have had direct contact with isis. And the department of Homeland Security keeping a close eye on the investigation. We begin with jennifer eccleston. Reporter tonight investigators scrambling to find evidence of an alleged plot to bring down an airliner. Heavily armed police, some in hazmat suits, others in gas masks, raiding homes across sydney, australia. Four men arrested. We do believe it is islamicinspired terrorism. Reporter officials believe the terror plan involved an improvised device, describing the plot as credible. Sources tell abc news that american intelligence officials are closely monitoring the case, because of suspected communications between the alleged plotters and isis. Also tonight, chilling new details from the newspaper, the australian. The suspects constructing an explosive device using poisonous gas that would kill or immobilize everyone on the aircraft. Abc news has not verified this report. If australian media reports are correct, this would be the first time we have seen any sort of terrorist act that involved gas on an airplane. Reporter the department of Homeland Security are assisting partners overseas and have taken extraordinary steps to protect flights bound for the United States. Airports across australia intensifying armed patrols, warning passengers of vigorous security. And jennifer joins us live from Londons Heathrow airport. Jennifer, what do we know about the suspects in this case . Reporter well, tom, the australian newspaper reporting the four suspects were dual citizens of australia and lebanon, and all four were reportedly related. Tom . Jennifer, thank you. Now to the growing tension with north korea after another missile launch. A pair of u. S. Air force bombers seen here in the military drill alongside south korea and Japanese Military planes as our military again tests its own Missile Defense system. The show of force after kim jongun claimed his second Intercontinental Ballistic Missile launch this month, now saying his arsenal has the power to strike the mainland of the United States. President trump now pointing the finger at china. Reporter a show of force in direct response to north koreas most alarming missile test yet. Two b1 bombers flying over the Korean Peninsula in a tenhour mission. The u. S. Also conducted a successful previously planned mediumrange Missile Defense test. Pentagon video shows a missile being detected and intercepted. But stopping an Intercontinental Ballistic Missile like the one north korea launched friday is even more difficult, like a speeding bullet hitting another speeding bullet. And north koreas latest missile traveled farther than any they have ever launched. It could potentially reach deep into the United States mainland. Japans nhktv captured a bright light falling into the sea of japan. This is here. They have been barking wolf about this while the wolf is at the door. This is a very real threat to the United States. Reporter with military Options Limited on sunday, President Trump called out china, tweeting, they do nothing for us with north korea. We will no longer allow this to continue. The white house is calling on china, north koreas only significant trading partner, to apply more pressure on the regime, arguing china has more direct influence than any other country. Tom . Gloria, thank you. Next to the white house. Badly in need of a reset and searching for a legislative victory. A daunting task after several shakeups. As President Trump urges Senate Republicans to push forward on a repeal and replace strategy that has yet to win support. President trump spotted dining last night with his new chief of staff, retired general, john kelly, at the Trump International hotel. And tonight a diplomatic dustup with russia and Vladimir Putin retaliating. Abcs david wright at the white house. Reporter tonight, as the president gets set to sign new russian sanctions, approved by congress, despite his own objections, the kremlin is retaliating. Vladimir putin appeared on National Television to announce the expulsion of hundreds of u. S. Diplomats. The largest forced reduction of the u. S. Embassy in moscow for nearly 100 years. Since the russian revolution. Here at home, challenges too. The president is making it clear, hes not ready to accept defeat on health care reform. Tweeting, dont give up republican senators. The world is watching. You cant promise folks youre going to do something for seven years and then not do it. Reporter but the republicans who voted against the bill have no regrets. Maines Susan Collins says she got a round of applause at the airport when she landed in bangor. It was just amazing. Ive never had that happen in the 20 years that ive been privileged to serve in the senate. Reporter President Trump has repeatedly said the only alternative to a repeal is to let obamacare fail. The best thing we can do politically speaking is let obamacare explode. It is exploding right now. Reporter he repeated that friday, after the senates vote. You know, i said from the beginning, let obamacare implode. And then do it. I turned out to be right. Let obamacare implode. Is that what hes going to do . I think, again, that punctuates the concern that he has. Reporter today health and Human Services secretary, tom price, insisted, trump is just trying to move the debate in the right direction. Thats why he keeps coming back to this, and saying, look, senate, do your job. Congress, do your job. Reporter the white house is hoping to turn the page after one of its most chaotic weeks yet. For the new chief of staff who starts tomorrow, a lot to fix. The president s former Campaign Manager has this advice. You have to let trump be trump, and anybody who thinks theyre going to change donald trump doesnt know donald trump. Reporter Corey Lewandowski there. With some advice. David wright joins us from the white house. David, what are the chances the president gets another vote on the Obamacare Repeal . Well see, tom. The senate is still technically in session. Theyre hoping to clear up the backlog on some of those administration appointments. They will face mounting pressure from the president to revisit obamacare, though. But chances are slim theyll do it before the august recess, tom. David wright for us at the white house. Thanks. Now to venezuela. An explosive new clash today during the vote on a constitutional assembly. Backed by the countrys president that has enraged the opposition. Take a look at this. A massive blast caught on camera in caracas. Several Police Officers injured, and at least three dead, across the country in voting today. Including two teenagers. One candidate for the assembly was fatally shot by a group of people who burst into his home. President Nicholas Maduro voting early this morning, for the special assembly of delegates to rewrite the constitution. Opposition leaders who are boycotting the election say hes looking to install an autocratic system. Next tonight, a shooting at an upscale vacation resort. An American Lawyer with his family targeted after a Security Guard was tied up. The second american tourist shot in two months. So are travelers to these popular islands now in danger . Heres abcs marcie gonzalez. Reporter a manhunt in the turks and caicos for a man who shot an american tourist. Michael jones and family were returning to this lavish beach front rental home friday when at 10 12 00 p. M. , two masked men forced their way in, overpowering the Security Guard on duty. The Security Guard had been lightly bound at the scene with his own shoelaces. Reporter jones, a prominent washington, d. C. , attorney and georgetown law professor, reportedly confronting one of the intruders who then shoots the 57yearold. The gunman only getting away with a laptop. What we dont know why a shot was discharged. What led up to that shot being discharged. Reporter jones transferred to a hospital in south florida, where tonight he is listed in stable condition. This luxury villa rents for more than 2200 a night on the caribbean island known as a popular celebrity destination, but now also gaining notoriety for violence. Kevin newman injured during a robbery in june, a bullet piercing his abdomen. We dont understand why it happened. Reporter turks and Caicos Police saying the crime rate on the island is increasing, but the american tourist shootings dont appear to be connected. When you come here, dont automatically assume that nothing can happen to you. Because we have criminals. Reporter but officials there insist, the country remains safe, and the state department has not issued any advisories for american travellers. Tom . Marcy gonzalez, thank you. Now to the desperate manhunt for an accused killer outside of minneapolis. A violent chain of events that forced the evacuation of a Senior Center and left one woman dead. That suspected killer is on the run. Heres the latest. Reporter tonight, a manhunt for a suspected murderer. Moments after an armed robbery, s. W. A. T. Teams on the scene, a sniper on the roof, in this minneapolis suburb. Authorities placing a busy Shopping Complex on lockdown, a Senior Center evacuated. Elderly residents, some in wheelchairs, led to safety. During the lockdown, a woman is found murdered in a nearby office building. I believe it was another worker in the building that found her. Reporter lucifer vincent nguyen, allegedly living up to his name. Police say he is the prime suspect, considered armed and dangerous. Police say 44yearold nguyen entered the Senior Center saturday with a handgun, but then disappeared. The last information we got was he entered in there and said something to some of the employees. Reporter nguyen reportedly taking off in this vehicle, crashing into a swamp before getting away on foot. I would presume by the time we had the perimeter set up he was already gone. Reporter police are working multiple leads as the suspect is on the run. Authorities say they have spoken with the victims friends and family who are staying strong tonight. Tom . Thank you. Next tonight, the Mass Evacuation from a popular tourist site. All nonresidents being told to leave parts of North Carolinas outer banks after construction crews severed three electrical cables that powered the islands. As crews attempt to fix the problems, Business Owners feeling the crunch during the most critical time of the year. Here is abcs eva pilgrim. Reporter tonight, a busy vacation destination now a ghost town. Two North Carolina towns on day three in the dark. Tourists told they cant stay, forced to go home. Its pretty disappointing. We had another day left. We wanted to be on the beach. Reporter the governor forced to declare a state of emergency. Mandatory evacuations turning some 50,000 people away. Local officials warning, those that do not comply with the order to leave will be issued citations. The nightmare began thursday in the outer banks. Construction crews working on a new bridge, drove a steel casing, cutting all three underground transmission lines to the area. Knocking out power. Businesses say the damage is done. The crowds are gone. Every day were not open, thats 5,000 in sales that were missing. And, of course, tomorrow when i finally get back in the restaurant will also be a problem. Reporter no word tonight on reporter power expected to be stored in one to two weeks, but Business Owners are worried. Because this is not a natural disaster. This is somebodys fault. And i hope they step up. Reporter generators have been brought in, so residents are being allowed to return, but they are being asked to conserve energy. Tom . The timing couldnt be worse. Eva, thank you. Now to what may be a deadly new chapter in a Treasure Hunt mystery. A colorado man found dead after he went missing. Friends say he was trying to solve a riddle, and cash in. Already two deaths tied to this hunt. Stephanie ramos with the new details, and what the man who hid the treasure is saying. Reporter tonight, the mystery deepening around a missing Treasure Hunter who disappeared while looking for gold and jewels in the rocky mountains. 31yearold eric ashbys friends say he moved to colorado to find 2 million worth of treasure. Supposedly hidden by this man. New mexico art dealer and collector, forrest fenn. The clues mapped out in fenns 2010 book, the thrill of the chase. When somebody finds that chest, theyre going to be shocked. Reporter police say a witness called 911 june 28th, saying a raft along the Arkansas River with multiple people in it capsized. Others got out. Ashby did not. But when police arrived, no one was there. Officials discovered human remains friday afternoon. But they have not yet been identified. Something happened down there that day, and we just want answers. Reporter the hunt for riches already blamed for two deaths. I want mr. Fenn to retrieve the treasure or call off the hunt after he retrieves the treasure. Fenn tells me he compiled a list of suggestions to make people safer when they go into the mountains. But regardless of the loss of life, he wont call off the Treasure Hunt. Tom. Stephanie ramos with that new reporting tonight. Stephanie, thank you. And theres still much more ahead on world news tonight this sunday. The skyhigh rescue, cable car riders, even a baby, trapped in the air. Plus, do your kids have it . The popular controversial new app some say leads to bullying. And the amazing leap taken by a man 102 years old. Stay with us. This is abc world news tonight brought to you by the venture card from capital one. Have. It could be better. Ou its time to shake things up. With the capital one venture card, you get double miles on everything you buy, not just airline purchases. Seriously, think of all the things you buy. Great. Is this why you asked me to coffee . Well yeah. But also to catchup. 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Reporter 15 million using sarahah, beating out instagram, youtube and snapchat for downloads in the free app store right now. The developer says it was intended to give reviews in the workplace, but some sounding the alarm in reviews, writing, it is just another outlet for people to be mean. Do not let your kids get this. They will be so sad. What are some of the signs kids are being bullied, specifically online. Are they not hanging around their friends. Are they a little despondent or sad . All those are things something is going on.