A military judge on Wednesday threw out Pfc. Lynndie England's guilty plea to prisoner abuse at Abu Ghraib, saying he was not convinced that she knew her actions were wrong at the time.
Col. James Pohl entered a plea of not guilty for England to a charge of conspiring with Pvt. Charles Graner Jr. to maltreat detainees at the Baghdad-area prison.
The mistrial for the 22-year-old reservist, who appeared in some of the most notorious photographs from the 2003 abuse scandal, kicks the case back to the military equivalent of a grand jury proceeding.
The action came after Graner, the reputed ringleader of the abuse, testified as a defense witness at England's sentencing hearing that pictures he took of England holding a naked prisoner on a leash at Abu Ghraib were meant to be used as a legitimate training aid for other guards.
Other photos showed England standing next to nude prisoners stacked in a pyramid and pointing at a prisoner's genitals.
When England pleaded guilty Monday, she told the judge she knew that the pictures were being taken purely for the amusement of the guards.
Pohl said the two statements could not be reconciled.
"You can't have a one-person conspiracy," the judge said before he declared the mistrial and dismissed the sentencing jury.
Under military law, the judge could formally accept her guilty plea only if he was convinced that she knew at the time that what she was doing was illegal.
By rejecting the plea to the conspiracy charge, Pohl canceled the entire plea agreement.
England's plea deal was a tightly woven package, reports CBS News Correspondent Barry Bagnato. When the judge decided he could not longer accept one of her guilty pleas, the remaining threads unraveled.
Army legal expert Capt. Cullen Sheppard says it's back to square one for England.
"The charges will be returned to the convening authority, the commander III Corps, for disposition," Sheppard said.
During defense questioning, Graner said he looped the leash around the prisoner's shoulders as a way to coax him out of a cell, and that it slipped up around his neck. He said he asked England to hold the strap while he took photos that he could show to other guards later to teach them this prisoner-handling technique.
At that point Pohl halted Graner's testimony and admonished the defense for admitting evidence that ran counter to England's plea on the conspiracy charge and one count of maltreating detainees.
The judge did not discuss the other five counts to which England had pleaded guilty.
Graner, who is said to be the father of England's infant son, was found guilty in January and is serving a 10-year prison term for his role in the scandal.
In a handwritten note given to reporters Tuesday, Graner had said he wanted England to fight the charges.
"Knowing what happened in Iraq, it was very upsetting to see Lynn plead guilty to her charges," he wrote. "I would hope that by doing so she will have a better chance at a good sentence."
Graner maintains that he and the other Abu Ghraib guards were following orders from higher-ranking interrogators when they abused the detainees.