If not regular civilian criminals, then I guess we have been releasing terrorists from Abu Ghraib by the hundreds for some time now.
More than 600 released from Abu Ghraib prison
May 29, 2004
ABU GHRAIB PRISON, Iraq – Raising their voices in slow, melodic chants of "God is Great," hundreds of Iraqis took over a highway in front of Abu Ghraib prison yesterday to greet buses carrying out 623 men and one woman after months of detention.
Nearly 300 Iraqis released from Abu Ghraib prison May 15, 2004
ABU GHRAIB, Iraq -- After months at Abu Ghraib prison, Hussein Sami did not complain of physical abuse upon his release. But Sami -- among 293 detainees freed Friday -- said guards shouted at and insulted inmates, and the prison was unsafe because insurgents target it with mortar rounds.
The release came a day after a surprise visit by U.S. Defense Secretary Donald H. Rumsfeld, who recommended decreasing the prisoner population.
More prisoners released from Abu Ghraib - May 28, 2004
US forces in Iraq have released more detainees from the Abu Ghraib prison outside Baghdad. Buses carrying the prisoners drove out of the complex as thousands of people gathered outside hoping for news of detained relatives. An American spokeswoman says up to 600 people were due to be freed. Last week, more than 400 people were released from Abu Ghraib, which has been at the centre of a scandal over the abuse of inmates.
There are plenty other instances. A google search will reveal all others.
You brought up the Geneva Conventions and guess what? Graner wasn't tried under them. You lose again!