It was the sixth life sentence for Luciano Menendez, 83, who was head of the army's Third Corps during the dictatorship period and was responsible for 11 provinces in central and northern Argentina.

On May 20, 1976, soldiers and provincial police under Menendez's command broke into a home in the northern city of Tucuman and killed five alleged members of the leftist Montonero guerrilla group. The bodies were then buried in a common grave.

Menendez was found guilty of twice-aggravated homicide and unlawful entry in the case, according to the verdict released by Argentina's judiciary branch.

Also guilty on the same charges and in the same case was former Tucuman province police intelligence chief Roberto Albornoz, the verdict read.

Both Menendez and Albornoz were ordered to serve their time in a prison for common criminals.

A broad amnesty approved after democracy was restored in Argentina was annulled during the 2003-2007 presidency of the late Nestor Kirchner, paving the way for a series of recent trials.

In all, some 30,000 people were killed under the dictatorship, according to rights groups.