BALTIMORE (WJZ) — Craigslist crime wave! Thieves are using the site to lure victims to a location and then robbing them at gunpoint. Now police are sounding the alarm.

Meghan McCorkell has more on this dangerous trend.

Police have linked four armed robberies to the same person posting on Craigslist. That gunman is getting away with thousands.

Rare coin collections and expensive watches are just some of the items people thought they were buying on Craigslist. But when they showed up with cash, they got a gun in their face.

“I’m surprised to hear something like that around here in this area,” said resident Darien Fowler.

“You can’t trust. There’s a lot of things about social networks that you can’t trust,” said resident Terrell Hickman.

Four people were robbed along Callaway Avenue. When one tried to run, the robber fired a shot.

“You have some suspects who are really preying on victims and they’re trying to be smart doing it,” said Anthony Guglielmi, Baltimore City Police spokesperson.

Craigslist has become a key tool for criminals. The most notorious is Phillip Markoff, known as the Craigslist Killer. He used the site to lure women to hotel rooms, killing one and assaulting several others.

“I can be the worst criminal in the world and I can say that I have things, lure people to it, take their wallets and run,” said Gary Buclous, Infoworks Technologies.

Buclous, a cybersecurity expert, advises asking questions about the seller before meeting them.

“They should give you their full name and address. Use Google Earth. Look at their house, see if they’re legit,” he said.

If you do buy something off Craigslist, police say you should pay by cashier’s check instead of cash. You should also meet the seller in a public area like a shopping mall or even outside a police station. These safety measures could save you from becoming a victim.

Police are looking into whether other robberies could also be linked to the same Craigslist poster. They are following several leads in the case.

So far, no one has been injured in any of the robberies.