Former prison sergeant Douglas Tower, already convicted of assaulting two female inmates, has told state officials he'll consider a plea agreement on the remaining 11 cases, said prosecutor Benjamin Agati of the state attorney general's office.

"There is a possibility of a plea, and that is in negotiations," Agati said Friday. "We did make an offer before the last case (went to trial in December), and he's asked us to make a new offer." The terms of a possible plea agreement have not been disclosed.

Tower, who is being held at the Merrimack County jail, could not be reached. His attorney, Adam Cook, declined to comment on a possible plea. Tower, 63, is already serving what could be a life sentence on his first conviction, which came with a 20 to 40 year prison sentence.

Tower was indicted in 2006 on 53 counts of rape, sexual and physical assault. The charges allege that Tower assaulted 13 female inmates under his supervision at the Shea Farm halfway house in Concord between January 2004 and January 2005.

The state tried Tower on the first set of charges in early 2007. That jury convicted Tower of six counts of rape and sexual assault against one of the women. He was sentenced to 20 to 40 years in prison.

In December, Tower was convicted again, this time for physically assaulting a former inmate by grabbing her by the neck during an "inmate count." A judge recently sentenced Tower to 1 to 5 years in prison on that charge and ordered that the time be served after Tower fulfills his first sentence.

Tower has appealed the first conviction to the state Supreme Court, which has not yet ruled. Tower also asked a judge to vacate the second conviction over a question of juror conduct during trial. That issue hasn't been decided either.

Agati said the state Supreme Court's decision on that appeal could influence any pending plea negotiations. If the court throws out the conviction, the 20- to 40-year prison sentence would be thrown out too.

Meanwhile, the state announced in March that it was paying $1.9 million to 30 inmates and one prison employee who accused Tower of raping or harassing them.

If Tower resolves his remaining criminal charges in a plea agreement, he will likely be sent out of state to serve his sentence because he used to work for New Hampshire's prisons. Jeff Lyons, prison spokesman, could not be reached to say where Tower may serve his time.

Cook raised Tower's poor health with the court during the last case. Cook said Tower suffers from coronary disease and has grown sicker since being incarcerated. State officials told the court that Tower is getting the best medical care available at the jail.

Tower's sister, Janice Parker, said Friday the criminal trials have been frustrating and difficult on Tower and the rest of her family, not only physically but also mentally.

"I just feel like they are using Doug as an example," she said. As for the number of accusers, she said, "I just think a lot of people jumped on the bandwagon." Parker also said it's "absurd" to think that Tower could have committed the alleged assaults given his heart condition, which bothered him even during his time at Shea Farm, she said.

She said she hopes her brother's lawyers will continue to raise his health concerns, even though they did not spare him prison time with the last sentencing.