Mark Jeffrey found dead in Ontario prison cell

Mark KingJeffrey, a man convicted of murdering a 13-year-old Iqaluitgirl in 2002, was found dead last night in his Ontario prison cell.

Jeffrey, 34, was serving a life sentence at medium-security Beaver Creek Institution in Gravenhurst, Ontario. In 2007, Jeffrey pleaded guilty to second-degree murder in the death of Jennifer Naglingniqin Iqaluit. The Grade 8 student was found stabbed to death in her home on Dec. 6, 2002.

At the time of Jeffrey's sentencing, NunavutJustice Earl Johnson described the murder as one of the most savage cases in the history of the Northwest Territories and Nunavut.

In a news release, Beaver Creek staff say that Jeffrey was found unresponsive in his cell on Monday night. Staff members immediately began performing CPR and emergency services were called, but he could not be resuscitated.

The cause of death has not yet been released.