Rise of the digi-lantes

Jake Gillum loved his bike. So when it was stolen in Portland, Oregon earlier this month he was determined to get it back. He spent days online searching for his carbon-fibre racer in what seemed like a hopeless quest, until he found it for sale in Seattle, 160 miles away.

What followed was an elaborate sting operation in which Gillum used an alias and an app to give him a disposable mobile phone number to trick the thief into meeting him. He confronted the criminal, caught the exchange on camera and gave chase when the thief bolted.

The video, which was uploaded to YouTube last week, ends when Seattle's finest arrive. Its highlights include Gillum chasing the bad guy and shouting: "This is why you don't steal from bicyclists, because we care about our rides! Because I will go 160 miles to get my $2,500 bike back!"

Gillum's internet vigilantism is only the latest example, though, as ordinary people use the hi-tech methods to reclaim their possessions. Last week Scottish biker Donald Pyper, 32, texted about 50 friends and used Facebook and Twitter to track sightings of his prized Harley Davidson after it was stolen (he got it back). And in London, where bike theft has risen by a third, people seek to track down their wheels by posting on social media.

Last April the ex-England rugby captain Will Carling used the Find My iPhone app to trace his stolen iPad to a block of flats in Woking and in California. Joshua Kaufman became famous after spending weeks gathering photos and location data using a software package called Hidden to track down his stolen laptop.

The police are catching on, too. After BBC's home affairs correspondent Tom Symonds was mugged near his home, the Haringey Robbery Squad used an iPad to track his stolen phone's GPS signal and collar the thief. Symonds was helped by the boys in blue, but is there a risk that going it alone will only get your head kicked in?

"Even without the police I would have tracked down my phone," Symonds says. "It's then a question of if you should march off, iPad in hand, to reclaim it. If I'd have done that I'd have probably ended up losing my iPad, too." Predictably, the Met is tight-lipped about victims taking justice into their own hands: "We welcome all the help people can give in investigating crimes, but you should always contact your local police station or call 999 if you have any information about a theft."

"You do need the police there to help you out," Symonds says. "You don't have the power to go to somebody, even if you think they are a criminal, and just demand they give up what they have on them."

Criminals are getting wise to this new crime-fighting phenomenon. Ian Hyde, 23, had his phone stolen at knife point in Brixton, south London, this summer. He had a tracking app installed and police quickly located his phone at a nearby shop. "Just as we arrived they lost the signal," Hyde says. "Most likely he'd taken the battery or SIM out, so there was nothing the police could do as they didn't have a warrant." Hyde is philosophical though: "While I was momentarily tempted to go in and get it, I didn't fancy going in there alone."