Suspect held in Craigslist killing charged in 2nd crime

— -- A Boston University medical student who appeared in court Tuesday on a murder charge searched Craigslist to find his victims, prosecutors say, highlighting the potential dangers of social networking websites.

Police in Boston and Warwick, R.I., say Philip Markoff, 23, may have preyed on other women he found on the website, where people can post most ads for free, says Jake Wark, a spokesman for the district attorney in Suffolk County, Mass., who brought the charges. A judge ordered Markoff jailed without bail.

He is charged with murdering one woman and robbing and kidnapping another. Both had posted ads under the website's "erotic services" section, police say.

Craigslist CEO Jim Buckmaster, in a statement posted on his blog Tuesday, urged website users to take "the same common-sense precautions online as they would offline," such as choosing a public place or bringing a friend along when meeting people encountered online. About 50 million Americans use Craigslist to place online classified ads each month, he wrote.

"We are horrified and deeply saddened that our community services have been associated in any way whatsoever with a crime of violence," he wrote. "We are evaluating this incident closely to see if there are any additional things (Craigslist) could be doing to further improve safety for our uses and the general public."

Defense attorney John Salsberg said Markoff is not guilty and "has his family's support."

"There are a lot of people out there, and not all of them are good," says Parry Aftab, a privacy and security lawyer who founded wiredsafety.org to promote online safety, including on popular sites such as Craigslist, Facebook and MySpace. "Many of us are vulnerable because we're not as careful in the online world as we would normally be."

This is not the first time someone allegedly has used Craigslist to find a victim. Michael John Anderson, 20, of Savage, Minn., was sentenced this month to life in prison for killing Katherine Ann Olson, 24, whom he lured to his home when she responded to an ad for a nanny he put on the site.