The state Department of Correction, staggered by a string of disclosures about its wrongful confinement of at least 14 inmates, said yesterday it is scrapping its system for calculating inmate sentences and is devising new methods to make sure prisoners serve only their legal terms.
At the same time the department also revealed that an inmate previously described to the Globe as having been held 34 days too long was actually released more than two years -- 790 days -- after he should have been.
Lawrence R. Burhoe of Charlestown, who served time for armed robbery and assault and battery with a dangerous weapon, learned of the mistake yesterday.
"How could they do that?" said Burhoe, who was released from prison last April. "I'm kind of overwhelmed. I had told them, 'I don't owe you any more time. My time is up.' "
The acknowledgement that the sentencing system will be overhauled comes eight days after Public Safety Secretary Kevin M. Burke said he was ordering a sweeping review of state prison operations after a Globe Spotlight Team report revealed a series of sentence miscalculations -- errors Burke called inexcusable.
One former inmate, Rommel Jones, was held more than four years after he should have been set free, the Globe reported. The department never informed Jones of the error or apologized for it; he learned of the years he had lost from a Globe reporter.
"The Rommel Jones incident has caused the DOC to examine the way sentence computation is done," the Correction Department said in a prepared statement. "Each facility had been preparing its own date calculation computation for submission to central classification. As of May 10, the DOC will implement a central system."
Asked whether any manager had been fired or demoted because of the errors, the department said it would not discuss "personnel issues." It has blamed the errors on the complexity of court decisions governing the terms of sentences.
"A team approach to review all date computation makes sense at this time," the department's statement said.
Diane Wiffin, a department spokeswoman, said she did not know precise details about how the new system would work or how much manpower would be devoted to it. "We're working on the plan now," she said.
The department expects to have the new system in place by July 1, with staff to be drawn "from those with expertise in the facilities."
Outgoing Correction Commissioner Kathleen M. Dennehy , who was asked to leave her post by the Patrick administration, will be replaced by a commissioner who, Burke said, will be responsible for making sure any sentence computation errors are corrected and not repeated.
Dennehy's deputy, James R. Bender, was named acting commissioner last week.
The late inmate releases are expected to be a focus of a legislative hearing this afternoon on Beacon Hill. Committees focused on public safety and mental health had scheduled a session to look into a spike in inmate suicide, which has plagued the correction department for more than a year. Lawmakers said the issue of wrongful imprisonment also will be examined.
Dennehy, who Wiffin said was not available for comment yesterday, is taking a job with the Bristol County sheriff's office.
In a mid-April memo to Burke, Dennehy explained that former inmate Jones, who was wrongfully imprisoned four years too long when he was released last July, was affected by a court decision whose terms were not obeyed by prison officials.
Jones went to prison on consecutive sentences, a 20-year term to be followed by another 10-year sentence. The 1995 court decision said that when an inmate is out on parole -- as Jones was three times -- the two sentences must run concurrently. The department did not take that into account.
After the Globe's initial inquiries, Dennehy, who said Jones would still be unaware of the error if the Globe had not called attention to it, said 13 other inmates had been imprisoned beyond their release dates.
They were notified about the mistakes in letters that were mailed late last month. In those 13 cases, the length of time of the wrongful confinement ranged from one day to 515 days.
James R. Pingeon, the director of litigation for Massachusetts Correctional Legal Service who is representing Jones, said he was contacted by Burhoe last week, days after he was informed that he had been kept in prison 34 days too long.
But late yesterday afternoon, Burhoe said he received a call from Carol Mici, the department's director of classification, who he said told him he was actually held 790 days too long.
"This was the result of a transcription error, not a date calculation error," the department said in a statement. "Nevertheless, a major error did take place again with regard to the information provided to this former inmate."
Like Jones, Burhoe said he had written to prison officials to complain about his sentence calculation. "I said I'm supposed to be getting out and [a prison staffer] said, 'No, you've got another 18 months.' I said I don't believe that. My time's supposed to be up."
When the initial error was discovered, Burhoe said his jailers at Souza-Baranowski Correctional Center in Shirley were eager to let him go. "When they released me, they said, 'We've got to get you out of here today.' I was just happy to leave after 25 years," he said.
Thomas Farragher can be reached at email@example.com