DERRY - The president of the police patrolmen's union is asking the Town Council to look into the retirement of three veteran officers, saying he believes at least one of them may have been forced out.

Sgt. Daniel Pelletier, Lt. Steven Inserra and Lt. Vincent Byron all indicated this week that they will retire in May, police Capt. Vernon Thomas said yesterday. Pelletier has been with the department for 24 years, Inserra for 22 years and Byron for 28 years. Thomas wouldn't say why the three officers are leaving.

But Michael Houle, president of the Derry Police Patrolman's Association, said Pelletier was not ready to leave and was retiring in reaction to being told he was being demoted from the detectives unit to the patrolmen's unit. Houle said he didn't know if Inserra and Byron were leaving for similar reasons.

"I know for a fact Dan Pelletier was not ready to leave," he said. "By moving Dan Pelletier out of detectives, they've taken a huge step backward. What an asset he is."

Houle is so upset at the prospect of losing all of that experience that he said he has asked the Town Council to look into the retirements.

"I would like to see the department reconsider that decision to move him," he said. "Leave him in detectives."

Town Councilor Kevin Coyle said he will ask the council to have the town administrator and the human resources director interview the retiring officers to find out what happened.

"Three retirements in a week should sort of set off bells in people's heads," he said.

Pelletier wasn't the only officer who was told this week that he was being reassigned.

Eric Brown, a former president of the union and 22-year member of the department, said he was told yesterday that he would be reassigned to general investigations after spending 14 years with the department's drug unit. Brown said he wasn't told why.

Peter Morelli, president of the Derry Police Supervisors Union, said he believes the moves were part of the department's effort to develop other officers.

None of the retiring officers could be reached for comment yesterday. Thomas wouldn't comment on whether any reorganization was taking place in the department, but he made it clear that none of the retiring officers was being disciplined.