On February 3, 2006, Craigslist was sued by the Chicago Lawyers' Committee for Civil Rights Under Law for allegedly allowing users to post discriminatory housing ads in Chicago that violate the Fair Housing Act. The case, Chicago Lawyers' Committee For Civil Rights Under Law v. Craigslist, was subsequently dismissed because of immunity granted by Section 230 of the Communications Decency Act.
On September 8, 2006, several sites reported that Craigslist's "Casual Encounters" forums in several cities had been compromised by individuals posting fraudulent ads in order to obtain personal information about people. This information, including email addresses, phone numbers, home addresses, photos, etc., was publicly posted online.
On September 12, 2007, a woman from Minneapolis, Minnesota pled guilty in federal court to running an underage prostitution ring through Craigslist.
On October 26, 2007, Katherine Olson, a Minneapolis woman, was found murdered in the trunk of her car after she responded through Craigslist to what she thought was a job as a nanny; the ad had actually been placed by "Craigslist Killer" Michael John Anderson. Anderson was convicted of his "Craigslist Killing" in 2009.
On February 8, 2008, a Michigan woman was charged with using Craigslist to hire a contract killer to murder a romantic rival in Oroville, California.
On March 22, 2008, Bernard George Lamp, 51 of Troutman, North Carolina was arrested for the murder of Bonnie Lou Irvine, 52, of Cornelius, North Carolina; she had agreed to meet him after he responded to her ad on Craigslist.
In April 2008, a Minneapolis couple were indicted for using Craigslist to advertise for sexual services, and then picking the pockets of those who responded. Eric Christopher Thorsen, 25, and Amy Ruth Bergquist, 30, then used stolen identification, checks and credit cards to purchase merchandise from online retailers as well as prescription drugs. In addition the couple was responsible for tens of thousands of dollars of bank fraud throughout the Twin Cities area. Thorsen and Bergquist ultimately pleaded guilty to trafficking in stolen documents and aggravated identity theft, and as of April 2009 are awaiting sentencing in US District Court.
In April 2008, a couple was charged with placing an ad on Craigslist inviting the public to take anything from a man's home in Oregon, leading to the loss of his possessions. The couple had placed this ad to cover up their own burglary of his house.
On May 27, 2008, in Vancouver, British Columbia, police reported that a Vancouver couple had attempted to sell its week-old baby on the site, but the couple claimed that it was merely a joke. The investigation is ongoing.
On November 7, 2008, after reaching an accord with over forty of the United States' top prosecutors, Craigslist announced that it would crack down on ads for prostitution by requiring people who post "erotic services" ads to provide a working phone number and pay a fee with a valid credit card.
On December 7, 2008, Matthew Hicks, 32, was fatally shot after robbing, assaulting and attempting to murder a man in Arlington, Virginia whom he had met through his girlfriend, who had met Donaldson via Craigslist; in January, 2009, Willie Donaldson, 35, was indicted for the murder but was subsequently acquitted on Jan 23.
On March 5, 2009, Cook County, Illinois Sheriff Tom Dart's Department filed a lawsuit against Craigslist, accusing the site of "knowingly promoting and facilitating prostitution" in its "erotic services" advertisement section. The company argued that it could hardly be expected to sift successfully through the vast volume of listings it received every day; nor was it required to by federal law; in fact, federal law protected it from criminal proceedings for failure to do so.
On March 20, 2009, the ABC radio news reporter George Weber was allegedly murdered by John Katehis in Brooklyn. The two had met via Craigslist; Weber was found bound and stabbed fifty times.
On April 20, 2009, Boston police arrested twenty-three-year-old Boston University medical student Philip Markoff of Quincy, Massachusetts, on suspicion of two cases of assault and robbery, and one of the murder of a woman whose services were advertised on Craigslist in Boston and Rhode Island, and whose corpse was found on April 14 in a Boston hotel. Allegedly Markoff first bludgeoned and then shot her with a gun, and, according to additional charges filed not long after, then robbed a stripper at a Warwick Holiday Inn two days later. He was arrested the following week while driving to a casino with his fiancée. He has pleaded not guilty.