Think twice before answering that ad: 101 murders have been linked to Craigslist

A post that appeared on Craigslist on Jan. 2.

This month, a disturbing missive appeared on the Craigslist page for Tulsa, Oklahoma.

"I was wanting to thank Tulsa for letting me have my first kill," the post begins. "It will not be my last thou."

The post has since disappeared from Craigslist, but not from the radars of concerned Oklahomans. A spokeswoman for the Tulsa Police Department said an investigation is ongoing. The homicide squad has found no open cases matching the murder described in the post, at least not within the past few months; they haven't ruled out the possibility that the post is a prank or a hoax.

Still, the post adds to a growing concern about Craigslist: that the site, far from just a good place to sell your stuff or meet a roommate, is also a platform for dangerous criminals to find their prey.

According to the Advanced Interactive Media Group, an industry watchdog and analyst, Craigslist passed the 100-murder mark just three weeks ago, when a 22-year-old man from Gary, Indiana, attempted to rob the middle-aged couple who'd arranged to buy his car.

"Their attitude is, 'We're safe, we have billions of safe transactions' - sure they do," said Peter Zollman, the founding principal of the AIM Group.

"But every single day, there are also rapes, robberies and murders linked to Craigslist. And that is a serious issue."

Craigslist has long maintained that the majority of its transactions are legitimate and that it can't be held responsible for the minority that aren't - which is true, legally speaking.

Still, some bad apples are active on Craigslist, and we don't tend to hear about them unless their crimes are particularly grim.

"Traditionally, the majority of murders were committed by killers who knew their victims," said Jack Levin, a Northeastern University criminologist.

"Thanks to the internet generally and Craigslist in particular, stranger homicides have been on the increase."

There are two things that make Craigslist a particularly attractive platform to would-be killers and other criminals, Levin said. First, Craigslist allows users to operate in total or near-total anonymity, meaning that they can both pretend to be just about anyone and can expect to meet a range of potential victims. Second, Craigslist postings don't require leaving a phone number - or even a name.

There's one more thing that makes Craigslist appealing to criminals, Levin explains: Craigslist is seen as having a "legitimate commercial purpose" that causes users to act more credulously. They're more willing to take risks, and tolerate eccentric or suspicious behaviour, because there's money on the table.