Massachusetts' state prison system proved to hold at least 14 inmates beyond their release dates, including one man who was jailed four years too long.
The Department of Correction in some cases failed to comply with a court order that modifies some sentences for time spent on parole, and otherwise relied on an inadequate computer system that tracks time served and good behavior credits, or simply botched the math, The Boston Sunday Globe reported.
"It's absolutely stunning incompetence," said James Pingeon, director of litigation for Massachusetts Correctional Legal Services.
Rommel Jones was released from prison in July 2006, four years after his sentence was completed. The 40-year-old was first arrested for shoplifting at age 17, and spent years in an out of prison, often returning because of possession of drugs.
Jones, diagnosed with schizophrenia in 1997, was unaware that his sentence was up in 2002, when he was denied parole.
The Department of Correction initially told the Globe that Jones' error was a bookkeeping anomaly. It later acknowledged it to be a serious error.
However, the department never told Jones of the mistake, even after releasing him last July. Jones learned of the mistake from a Globe reporter.
DOC Commissioner Kathleen Dennehy, who is leaving her post next month to take a job in the Bristol County Sheriff's office, said Jones' mental illness would have made it difficult for him to understand what happened.
"I think we could have been criticized for explaining this to someone ... with the history of mental illness that this individual has," she said.
Jones, who missed his mother's wake and lost contact with his daughter in the four years he spent wrongly held, called Dennehy's explanation "horrible."
"That's one of the saddest excuses that I've ever heard," he said. "All she had to do is just try me. I'm more intelligent than they know."
Dennehy, in sworn testimony in 2005, said the sentence tracking system has flaws.
"I think it is fair to call is a mess," she said in testimony for a whistleblower lawsuit brought by a department employee who complained she was transferred in retaliation for raising concerns about the inadequate tracking system.
Prison officials said they have reviewed their records to make sure no one else is affected. Dennehy said in a memo last week to new Public Safety Secretary Kevin Burke that the department's technology staff is studying how to avoid similar errors.