Police in London, Ontario say the murder of an 18-year-old man over the weekend highlights the risks of tracking down missing smartphones using mobile apps.

Jeremy Cook was killed Sunday when he tried to recover his lost smartphone from the people who had it, reports CTV News.

Cook thought he had lost his phone in a taxi. An online tracking tool located the missing device at a community strip mall. He and a relative approached a silver 2004 Mazda with three people inside shortly after 5 a.m. on Sunday, police said. The car started to drive away. When Cook grabbed the car door handle, he was shot multiple times.

Police told CTV News the three suspects fled, eventually crashing the car and abandoning it. Cook's cellphone was located near the vehicle.

Investigators are searching for three black male suspects between the ages of 18 and 21, according to CTV News.

Cook had no criminal record and did not know the three suspects.

Cook's friend, Kasia Szymanski, is devastated over his death, which she described as "senseless and cruel."

"And over what, a phone?" she added.

While cellphone tracking apps are useful, once the phone is located, if the situation appears threatening, it is best to contact police for assistance.

London Constable Ken Steeves told CTV News, "The app is not what makes the scenario dangerous, it's the people you interact with. Our advice is if there is any indication of violence, or potential violence, just give us a call and we'll attend."

Technology analyst Carmi Levy said that young people tend to have an emotional attachment to their smartphones due to the amount of personal data stored there. The attachment can cause youths to overvalue their phones. "It's a couple of hundred bucks to replace it -- certainly not worth your life," he said.

Cook was living in London for a carpentry internship. He planned to attend college in the fall. He was also operating a furniture business on the side, according to CTV News.