Oklahoma inmate faces trial in death of another inmate

Gregory Thompson is charged in the Sept. 3, 2009, stabbing death of 38-year-old Daniel Clayton. A local newspaper reports that prosecutors initially charged Thompson with first-degree murder before downgrading the charges to first-degree manslaughter.

Court records say officers found Clayton unresponsive in his cell, covered in blood. According to the records, Thompson allegedly handed the officers a knife and said he stabbed Clayton in self-defense.

Thompson is now serving a life sentence without parole for a 2003 first-degree murder conviction out of Oklahoma County.

His trial is set to begin Tuesday.