An 18-year old was shot and killed in London, Ontario over the weekend, after confronting three people he believed stole his smartphone. He had used an online tracking tool to locate the missing device.

Jeremy Cook lost his phone in a taxi, and traced its whereabouts to a strip mall in the local area, using an unnamed smartphone tracking system. Accompanied by another person, he approached a parked car. There are no details about what happened between next, but as the car started to drive away, Cook grabbed the door handle, and was shot multiple times.

Related: How to track a lost smartphone

The car was later found by police crashed and abandoned, and Cook's phone was also discovered nearby. Reports say Cook had not been in trouble with the police before, and didn't know the three people in the car, all of whom are still at large.

Police are taking the opportunity to tell people that while tracking lost phones is a useful tool to have, if the situation appears dangerous or threatening, it's time to call them in. Constable Ken Steeves of the London police told CTVNews, "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."

An analyst for IDC Canada said the amount of personal data we store on our smartphones, and the level of emotional attachment it can produce, may cause people "to not be as cautious as authorities might wish us to be." Most of the time, however, services such as Find My iPhone are used to locate a lost phone, without any interaction with another person at all.

Cook's friend Kasia Szymanski said Cook's death was "senseless and cruel," adding, "And over what, a phone?"