Braintree High School graduate Amy Bishop pleaded guilty to capital murder and attempted murder in Alabama on Tuesday, changing her earlier insanity plea.

The former professor at the University of Alabama in Huntsville admitted to shooting to death three colleagues and wounding three others during a meeting at the university in 2010, according to a report by the Associated Press.

In Massachusetts, the 47-year-old Bishop is charged with murdering her brother Seth Bishop, an 18-year-old at the time, with a shotgun in the family home in Braintree. That incident was originally labeled an accident until the Alabama shooting prompted officials to re-examine the 1986 slaying.

Bishop will likely avoid the death penalty and receive a penalty of life in prison because of her plea, the Boston Herald reported, but the sentence is not yet certain. Sentencing could come later this month.