U.S. Ambassador James Foley said the release on Thursday of Louis Jodel Chamblain, who helped lead the armed rebellion that drove president Jean-Bertrand Aristide from power last year, was proof that Haiti's judicial system was not working.

Chamblain is a former army officer who was one of the leaders of the paramilitary group Front for the Advancement of Progress of the Haitian People, which was blamed for some 3,000 deaths after a military coup ousted Aristide in 1991 during his first presidency.

"The release of Chamblain is a scandal for the country and for its image around the world," said Foley, who is about to leave his post in Haiti.

Chamblain was convicted of the 1993 murder of a Haitian businessman and for the 1994 killings of more than two dozen people in the northern city of Gonaives.

He surrendered in April 2004 under international pressure. His convictions were overturned but Haitian authorities continued to detain him on other allegations.

Chamblain was released on Thursday after judicial authorities decided there was no evidence to hold him.

"We know that he is a man who had been found guilty on several occasions of horrible crimes," Foley said. "Imagine, one moment, the tarnished image of Haiti today, with Chamblain being released and a former prime minister who continues to stagnate in prison."

Neptune, who served as prime minister under Aristide, was arrested in June 2004 on allegations he masterminded killings in the village of La Syrie in February 2004.

Neptune has denied the accusations and has accused the U.S.-backed interim government of holding him for political reasons. Human rights groups have criticized the government for jailing hundreds of Aristide supporters.

Foley said Neptune's detention was a violation of human rights and questioned whether he was involved in the deaths in La Syrie.

"Was he part of it, did he give any order?" Foley said. "No one has ever provided the least evidence, the least clue, the least testimony about Neptune's involvement ... They bear a grudge against him for Aristide's legacy."

Aristide left Haiti on Feb. 29, 2004, in the face of an armed rebellion and under pressure from Washington and Paris. He is living in exile in South Africa.