PORTLAND, Maine — A Lewiston man who spent decades behind bars on a murder conviction was sentenced Monday in U.S. District Court to two years and three months in federal prison for threatening to kill an official with the Social Security Administration in Baltimore.

In addition to prison time, Harold Rowe, 55, was sentenced by U.S. District Judge D. Brock Hornby to three years of supervised release.

Rowe pleaded guilty in August to the charge of mailing threatening communications to the deputy commissioner for Budget, Finance and Management of the Social Security Administration in September 2011.

Rowe was convicted of murder in the December 1982 shooting death of Michael G. Moore, 24, of Westbrook in what police described as a drug-related killing, according to a previously published report.

In the rambling letter with multiple misspellings to the victim that was quoted verbatim in the indictment, Rowe said he had been released in May 2011 after serving 27 years in prison for murder.

“I am a killer,” he wrote. “I have been envolved with murder since that time it just not have been cought up with me. So to tell you if you Try or do stop my check each month and give it to Somebody that if you dont stop your issue and send my check to anybody diffent than to who I already am recieveing threw the creidit union I will most likely kill somebody else because I will have nothing else to do.”

Rowe was arrested on Feb. 2 after being indicted the previous day by a federal grand jury. He has been held without bail since his arrest, and four days later was ordered to undergo a psychological evaluation. Hornby found in June that Rowe was competent to enter a plea and assist in his own defense.

Rowe faced up to 10 years in prison and a fine of up to $250,000. Under the prevailing federal sentencing guidelines, he faced between 21 and 27 months in federal prison.

The time he has been held without bail will be applied to his sentence.