Amy Bishop, former Biology professor at the University of Alabama- Huntsville has pleaded guilty Tuesday for opening fire at a faculty meeting in 2010 and killing three and wounding three other colleagues, reports Reuters.

Bishop has pleaded guilty to one count of capital murder for the death of two or more people and three counts of attempted murder. Earlier, she had pleaded not guilty in an attempt to use insanity defense. But, now with her new plea, prosecutors are taking death penalty off the table and she will face up to life in prison without parole in exchange for it.

The details on what prompted the agreement between prosecutors and the defense is not clear as of now.

Sentencing will follow a brief trial Sept. 24 before Madison County Circuit Judge Alan Mann. In the trial, a jury must decide the punishment for the capital murder charge. But, attorneys in the case will likely ask jurors to confirm that life in prison without parole is the appropriate sentence, according to Richard Jaffe, a defense attorney not connected to the case.

The Harvard trained biologist and a mother of four was initially thought to have had mental problems, but later the prosecutors argued that she was angry at the university for denying her a tenure which may very well have resulted in the loss of her job.

The February 2010 Alabama Campus killings led the authorities to reevaluate her previous brushes with law, which resulted in charging her in the death of her brother in 1986 in Massachusetts.

Her attorney in the Massachusetts case said to AP that it will be up to the authorities to decide whether to put Bishop on trial for murder in her brother's killing, now that she has pleaded guilty in Alabama.

The Massachusetts authorities have confirmed that they will be deciding on the case only after the sentencing in the Alabama shooting.

Bishop's shooting took life of her boss and biology department chairman Gopi Padila, professors Maria Ragland Davis and Adriel Johnson. Professors Joseph Leahy, staff aide Stephanie Monticciolo and assistant professor Luis Cruz-Vera were shot and wounded.