A convicted murderer accused of killing a state prison guard in Jessup seven years ago has, for a second time, been found mentally incompetent to stand trial after a hearing in Anne Arundel County Circuit Court.

Doctors for the state who evaluated Lamarr Harris, found he would not be able to assist his lawyer in a trial in the death of Cpl. David McGuinn, Anne Arundel State's Attorney Anne Colt Leitess said.

McGuinn was stabbed to death at the Maryland House of Correction in July 2006. Harris, now 42, is being treated at Clifton T. Perkins Hospital in Jessup.

The finding was not contested and no arguments were heard in the hearing Tuesday, which went about 30 minutes before Judge Paul A. Hackner ruled that Harris was incompetent to stand trial. Harris was represented by two lawyers from the Maryland Office of the Public Defender.

Leitess said she could not elaborate on the contents of the doctors' report, which she said is not public information.

Another hearing has been scheduled for February 2014. After the first finding of incompetency, the law requires at least one competency hearing a year, but more than one hearing can be held.

The state has five years after the initial finding, until June 2017, to put Harris on trial. He is charged with first-degree murder and conspiracy to commit murder.

Harris' lawyers could not be reached for comment.

Harris is already serving three consecutive life sentences plus 90 years in connection with two killings that took place in Baltimore City in 1989, but Leitess said the McGuinn killing case has to be pursued.

"Mr. Harris needs to be held accountable for what he did," she said. "We take these matters very seriously."

She said McGuinn's killing spotlighted reasons why the Maryland House of Correction, built in the 19th century, had to be closed. The antiquated prison was shut down in March 2007, less than a year after McGuinn was killed while conducting routine cell checks.

Harris was charged in McGuinn's death along with Lee Edward Stephens, who was convicted. Stephens' sentence added another life sentence to one he was already serving in a 1997 killing.

arthur.hirsch@baltsun.com