In this June 22, 2009 file photo, former Boston University medical student Philip Markoff stands during his arraignment in Suffolk Superior Court in Boston, on charges he killed a masseuse at a Boston hotel that he met through Craigslist. Officials confirmed that Markoff was found dead of apparent suicide in his jail cell Sunday, Aug. 15, 2010 in Boston. (AP Photo/Bizuayehu Tesfaye)

Philip Markoff, known as the Craigslist Killer after he was accused of killing a masseuse he met through the popular online classifieds site, was found dead this morning in his jail cell.

Markoff, a 24-year-old former Boston University medical student, was found unresponsive inside Nashua Street Jail in Boston and was deemed dead at about 10:15 a.m.

He was accused of killing two women–Julissa Brisman, from New York City, and a Las Vegas woman–in a four-day span in April 2009 at hotels in the Boston area. Markoff pleaded not guilty in relation to both incidents. In the same span of time, he was accused by Rhode Island prosecutors of attacking a stripper.

Markoff was engaged during the events and subsequent arrest to Megan McAllister, who broke the relationship off after visiting him in jail.