At this point it is not clear what the app Jeremy Cook used was, or what type of phone he had, but appears he thought that by showing up at the thieves' house he would get his phone back.

After leaving his phone in a taxi, Cook traced it to an address on Highbury Avenue and then he went to find it with a relative. When he arrived at the address, he was confronted by three young men in a car. It's not entirely clear what happened next, but police say that the vehicle began to drive away when Cook tried to get his phone back, at which point he grabbed on the driver's side door. Shots where then fired at him, and he ultimately died.

The car and phone have been recovered later, but Cook's attackers are still missing, with police looking for three men with ages between 18 and 21.

It is the first case of serious violence from someone tracking a lost smartphone online.

The Police said that while the app itself is a great tool. Nobody could ever predict that what occurred was going to occur in that case.

"But if you suspect there's any potential for violence at all, we certainly encourage people to contact police. We'd be more than happy to come out and investigate with the hopes of retrieving the phone," a Police spokesman said.