What to know about the Tree of Life trial

The trial of Robert Bowers, 50, of the Pittsburgh mass shooter who killed 12 people at the Tree of Life*Or L’Simcha synagogue

At the time of the attack, the Tree of Life*Or L’Simcha synagogue, which sits in a friendly neighborhood with a rich Jewish history, was home to three separate congregations, all of which were gathering for services in different parts of the building. The Tree of Life congregation founded in Pittsburgh more than 150 years ago, and the smaller New Light congregation, are both conservative, while Dor Hadash is a progressive movement within Judaism.

The trial will begin with guilt and continue with the penalty. As the facts surrounding the shooting are mostly undisputed, it will effectively be a monthslong tribunal about whether the defendant, Robert Bowers, 50, should be executed. His lawyers had offered to resolve the case by pleading guilty to all charges and then life in prison without the possibility of parole, but federal prosecutors have turned that down.

Mass shooter trials are rare, given that they often end with the death of the attacker. The man who killed 12 people in a movie theater in Colorado in 2012 was sentenced to life in prison after a trial, while the man who killed nine people in a church in South Carolina in 2015 was sentenced to death. The former student who killed 17 people at a high school in Parkland, Fla., pleaded guilty but faced a sentencing trial last year, where a jury voted to keep him in prison for life.