PITTSFIELD, Mass. — A New Marlborough man pleaded guilty on Tuesday to murdering his mother three years ago.

Rodney M. Ball, 38, was given a life sentence in the murder of 55-year-old Donna Agar, to be served at the Massachusetts Correctional Facility at Cedar Junction.

Appearing before Judge John A. Agostini on Tuesday afternoon, Ball pleaded guilty to single counts of murder in the second degree and illegal possession of a firearm, for which he was given a concurrent 2 1/2- to three-year prison sentence.

Ball, a lumber yard worker, had been held without bail at the Berkshire County House of Correction since first being arraigned on Agar's murder in March 2008.

Agar was found in a pool of blood at her home on Clayton Mill River Road in Southfield on the afternoon of March 16, 2008, after state police were contacted to do a wellness check after Ball drove her minivan to confront his estranged wife. Ball arrived at the scene while police were there and they found a rifle in the vehicle.

An autopsy found Agar had died from multiple stab wounds to the neck and chest and loss of blood. Ball, then living on Clark Way, told investigators his mother had killed herself.

The investigation was conducted by members of the New Marlborough and Sheffield police departments, state police detectives assigned to the district attorney's office, troopers assigned to the Lee barracks and the Crime Scene Services Section of the state police.