An Argentine federal court has opened the trial of a former police investigator who is accused of human rights abuses during the country's military dictatorship from 1976 to 1983.

Miguel Etchecolatz sits in court in La Plata, June 20, 2006

Miguel Etchecolatz is the first alleged human rights violator to be put on trial since Argentina's Supreme Court last year scrapped an amnesty for members of the former regime.

Etchecolatz appeared in court Tuesday in La Plata, southeast of Buenos Aires, to face charges of kidnapping, torture and murder in connection with the deaths of five people. He did not make a statement as the proceedings began.

Outside the court, protesters shouted insults at the 76-year-old defendant, accusing him of "genocide" and calling him a "murderer".

More than 100 witnesses are expected to testify in the trial, which could last for several weeks.

U.S.-based Human Rights Watch says Etchecolatz's trial marks the end of 20 years of impunity for regime officials who carried out the so-called "dirty war" against political dissent.

Argentina's Supreme Court struck down two amnesty laws last year that shielded hundreds of former regime officers from prosecution.

Etchecolatz was convicted in 1986 on several counts of illegal arrest and sentenced to 23 years in prison.  He was released the following year under a law that restricted most "dirty war" prosecutions to commanding officers.

In a separate case, Etchecolatz and another former police official (Jorge Berges) were sentenced to seven years in prison in 2004 for stealing babies from detainees during the military dictatorship.