NEW YORK – The last man to see the Tsarnaev brothers together alive was the unlucky owner of the Mercedes-Benz SUV they car-jacked.The victim told authorities that the two perpetrators of last week’s Boston Marathon bombings wanted to drive his car to New York, where they would continue their assault with a remaining arsenal of gun ammunition and at least six bombs.The New York Times cited federal sources that say the Tsarnaev brothers told the SUV owner their next destination was New York City. But a source in the Boston Police Department allegedly told the New York Daily News that the driver heard only the word “Manhattan” in English, as the brothers were speaking almost entirely in their native Chechen tongue.Either way, experts say the ability of the Tsarnaev brothers to leave locked-down Boston and enter the New York metropolitan area – roughly a five-hour drive – would likely have been hindered by the real-time surveillance net cast over the region by the many private citizens actively following the story on social media.“There aren’t police checkpoints for entry – like Boston, it’s an open city, though Manhattan does have fairly well-monitored toll stations and bridges,” said Phillip Carter, a senior fellow at the Center for a New American Security in Washington, adding that the NYPD has a domestic counterterrorism force that rivals the FBIs.“Fortunately we don’t live in a police state and even the most aggressive law enforcement can’t hermetically seal a city the size of Boston. But those two couldn’t stop for gas or get a bite to eat without detection, and that was a brilliant move by law enforcement,” away from relying on reactionary surveillance video, Carter added.The flurry of reports were accompanied by additional claims in The Boston Globe that the Chechen pair might have been involved in a triple murder a mile outside Brandeis University near Boston, in September 2011.Three Jewish students were killed in what remains an open homicide investigation, local officials told The Jerusalem Post. One of the victims was a close friend of Tamerlan Tsarnaev, the older brother, who failed to attend his friend’s funeral.But sources close to the investigation told the Post that the story is “getting way overblown” by the Globe and other outlets, and that it likely doesn’t lead “where people think it leads.”As other story angles trickle out from Boston, a motive for the alleged bombers has begun to crystallize: extremist religious views aggravated by ethnic tensions.In an interview with the Associated Press, Elmirza Khozhugov – the brother-in-law of the Tsarnaev pair – said that Tamerlan began visiting conspiracy sites as his Muslim faith underwent radicalization. Ultimately, Khozhugov said, Tamerlan sought out a copy of the virulently anti- Semitic Protocols of the Elders of Zion.But the reports coming out of US media outlets paint a hazy picture of what happened, reflective of the ongoing media frenzy over the extraordinary story which is still unfolding in New England.