WARREN — A man serving a 58-year prison sentence for fatally stabbing a Bates College student in 2002 has been charged with using a homemade knife to attack another prisoner.

Brandon M. Thongsavahn, 34, made his initial appearance Monday in Knox County Unified Court on charges of aggravated assault and trafficking in prison contraband.

According to the criminal complaint filed in court, the 34-year-old Thongsavahn stabbed Richard B. Coleman, a fellow prisoner, at the Maine State Prison on Aug. 2, 2016. The contraband charge stems from the homemade knife known as a shank that Thongsavahn had in his possession.

Thongsavahn asked to plead guilty to the charges, but District Court Judge Susan Sparaco said no plea would be accepted at the initial appearance. She asked him whether he wanted an attorney to be appointed by the court and Thongsavahn said he did.

Thongsavahn was twice convicted in jury trials of murdering Morgan McDuffee on March 2, 2002, on Main Street in Lewiston. His first conviction was overturned by the Maine Supreme Judicial Court, which agreed that the trial judge erred in allowing the prosecution to introduce unfairly prejudicial evidence of Thongsavahn wearing a T-shirt with profane language on it on the night of the killing.

McDuffee, of Peterborough, New Hampshire, was a senior at Bates just a few months shy of graduation when he was stabbed five times in the back and chest during a fight between college students and young people from the Lewiston area.

The state high court rejected in January 2007 an appeal by Thongsavahn of the second conviction, which was rendered in January 2006.

Assistant District Attorney Christopher Fernald said Thongsavahn has about 50 years left to serve.

He is next scheduled to appear in court on the charges on June 1.

The extent of the injuries sustained by the other prisoner was not immediately available. Coleman was in the prison serving a two-year sentence for burglary. The state prison website states that Coleman is scheduled to be released on April 27.