BUENOS AIRES, Argentina (AP) — An Argentine court is sentencing a former navy captain known as the "Angel of Death" to life in prison for dictatorship-era human rights violations committed at a clandestine detention and torture center.

Alfredo Astiz sat motionless Wednesday as a judge read the charges against him. They included kidnapping, torture, homicide and the stealing of minors. Astiz was already serving a life sentence.

Sentences against 53 other people were still being read in the largest trial of its kind in Argentina's history.

It involved crimes against humanity committed against 789 people at the Naval Mechanics School - the era's biggest clandestine torture center. Prosecution of those crimes began in two previous trials in 2007 and 2009.

Human rights groups estimate about 30,000 people were killed or disappeared during the 1976-1983 dictatorship.