|The strongest evidence against Graner and his accomplices were photographs of human rights abuses [Reuters]
The convicted ringleader of detainee abuses at Abu Ghraib has been released from a US military prison, an army spokeswoman said.
Charles Graner Jr was released on Saturday from the US Disciplinary Barracks at Fort Leavenworth, Kansas, after serving more than six and a half years of a 10-year sentence, spokeswoman Rebecca Steed said.
Graner, 42, will be under the supervision of a probation officer until December 25, 2014, she said.
Steed said she could not release any information about Graner's whereabouts or his destination after release. Graner's wife was a fellow Abu Ghraib defendant.
Graner was an Army Reserve corporal when he and six other members of the Maryland-based 372nd Military Police Company were charged in 2004 with abusing detainees at the prison in Iraq.
The strongest evidence was photographs of grinning US soldiers posing beside naked detainees stacked in a pyramid or held on a leash.
The pictures complicated international relations for the US and provoked debate about whether harsh interrogation techniques approved by the Pentagon amounted to torture.
Graner was convicted of offenses that included stacking the prisoners into a pyramid, knocking one of them out with a head punch and ordering prisoners to masturbate while soldiers took pictures.
He maintained that the actions were part of a plan directed by military intelligence officers to soften up prisoners for interrogation.
Graner is the last Abu Ghraib defendant to be released from prison and received the longest sentence.
Steed said Graner's obligation to the military ends at the end of 2014. Until then, his supervised release could be suspended.
She said Graner, who was a civilian correctional officer, was released before serving his maximum sentence under rules that include days off for good behaviour.
The spokeswoman said Graner had lost some good conduct time for institutional rule infractions while incarcerated, but did not provide details.
During his deployment, Graner fathered a son with former Army Private Lynndie England. England was given a three-year sentence for her role in the scandal.
After his conviction, Graner married another member of his unit, former Specialist Megan Ambuhl.
Ambuhl. was discharged from the army after pleading guilty to dereliction of duty for failing to prevent or report the maltreatment.
Seven guards and four other low-ranking soldiers were convicted of crimes at Abu Ghraib.
Former army prosecutor Christopher Graveline portrayed Graner in his 2010 book, "The Secrets of Abu Ghraib Revealed'', as a manipulative bully with the bad-boy charm to draw others into his sadistic games.
Lawyer Charles W Gittins, who represented Graner in an appeal to the military's highest court last year, described Graner in court as "a political prisoner of the failed United States Iraq policy and unnecessary