(CNN) -- Amy Bishop Anderson -- the professor accused of shooting six of her colleagues, killing three -- pleaded guilty to attempted murder charges on Tuesday and agreed to plead guilty to a capital murder charge in two weeks.
Appearing in Madison County Circuit Court, Bishop Anderson accepted an agreement with the state and pleaded guilty to three counts of attempted murder. She also faces one count of capital murder.
Bishop Anderson will plead guilty to the capital murder charge before a jury on September 24, according to CNN affiliate WAFF. Under Alabama law, juries are required in capital murder cases even when a plea agreement has been reached.
According to the terms of the plea deal, Bishop could be sentenced to life in prison for each of the attempted murder charges.
Prosecutors say Bishop Anderson, who taught at the University of Alabama-Huntsville, killed department head Gopi Podila and associate professors Maria Davis and Adriel Johnson during a biology department faculty meeting on February 12, 2010.
Bishop Anderson, a Harvard-trained geneticist, had been denied tenure at the university a few weeks before the shootings.
WAFF reported that prosecutors said Bishop Anderson's pleas on Tuesday confirm the facts of the shootings. The jury on September 24 will hear a shortened version of the case.
A judge in March 2010 placed a gag order on attorneys and law enforcement personnel prohibiting them from talking to the media.
Bishop Anderson also has been also charged in Massachusetts with the murder of her brother, Seth, in 1986. Her brother's shooting originally had been ruled an accident, but the case was reopened after the Alabama shootings.
Amy Bishop, who was 21, told authorities she had asked for her 18-year-old brother's help unloading a shotgun and it accidentally discharged.