A man convicted of killing a Waterville woman in 1991 died in prison on Tuesday after being attacked by a fellow inmate, accoridng to a news release from the Maine State Prison.

At the time of his death, Alan Powell, age 57, had served approximately 22 years of a life sentence at the Warren facility.

Powell was convicted in 1991 of the 1989 murder of 64-year-old Martha Daigle. Powell stabbed and strangled Daigle in her Waterville home.

State Police on Wenesday afternoon confirmed that Powell died after being attacked by another convicted murderer housed at the prison.

Detectives say he was attacked by 42-year-old Guy Hunnewell, who is serving a 40-year sentence for stabbing to death his girlfriend in Fairfield in 1997.

Hunnewell remains at the prison. Detectives went to the prison last night and conducted interviews with guards and inmates.

The case will likely be presented to the next session of the Knox County grand jury in July, according to State Police spokesman Steve McCausland.