Mexico's independent National Human Rights Commission said torture was used to extract a confession from one of the suspects in the January 2010 killings of 15 high school students at a party in Ciudad Juarez.

The panel formally asked authorities in Chihuahua state to investigate the abuse of Israel Arzate.

The case highlights "serious flaws in the new system of criminal justice," according to the Miguel Agustin Pro Juarez Human Rights Center, a non-governmental organization.

Arzate "was tortured to confess to having participated in the Villas de Salvarcar massacre," the center said.

The Washington Office on Latin America, a U.S. NGO, first raised the alleged torture of Arzate in a report issued last October.

Arzate, who sold CDs at a market in Juarez, was picked up on Feb. 3, 2010, by police and soldiers and then taken to an army barracks were he was "tortured physically and psychologically," WOLA said.

Authorities were actually looking for another man, but settled for Arzate, whose family only learned of his arrest when they saw him identified on television as one of those involved in the slaughter of the teenagers, WOLA said.

Insisting on his innocence, Arzate said interrogators subjected him to electric shocks, put a plastic bag over his head and told him his wife was in the next room and threatened to rape her.

Arzate eventually yielded to the threats and abuse and confessed to having acted as a lookout for the shooters who perpetrated the Villas de Salvarcar bloodbath.

Jose Antonio Acosta Hernandez, a Juarez drug cartel capo thought to be behind at least 1,500 murders in Chihuahua, told investigators that he ordered the massacre because some members of the rival Artistas Asesinos gang were attending the birthday party.

Acosta made the admission after his arrest early last month.

He said he commanded about 45 gunmen ranging in age from 18 to 25 whose mission was to eliminate officials, police and members of the Sinaloa cartel, which the Juarez organization has been fighting for control of Ciudad Juarez, located across the Rio Grande from El Paso, Texas.

The war between the cartels is blamed for some 9,000 killings in Juarez in the past five years.