A military judge has rejected the guilty plea entered by US soldier Lynndie England in her trial over the abuse at Abu Ghraib prison in Iraq.
Pte England's defence will have to think again
Judge Colonel James Pohl declared a mis-trial and entered a not guilty plea on her behalf.
He said testimony given during the sentencing phase contradicted Pte England's own statements and could not be reconciled.
Pte England's case will be sent back to military authorities to start again.
Images of US soldiers with naked Iraqi prisoners, including Pte England holding a prisoner on a leash, sparked widespread condemnation of US practices in Iraq.
Earlier this week she pleaded guilty to seven charges after negotiations with the prosecution in the hope of receiving a lighter sentence.
They included a charge of conspiring with her former boyfriend, Pte Charles Graner, to maltreat detainees.
Two other charges were dropped.
Graner, who has already been jailed over the scandal, said he had ordered Pte England, 22, to perform some of the now infamous acts of abuse.
Pictures such as this one showing Pte England shocked the world (AP Photo/Courtesy of The New Yorker)
He said the pictures he took were meant to become a legitimate training aid.
However, Pte England testified at the court martial in Texas that she knew the pictures were taken purely for the amusement of the guards.
Col Pohl said the two statements could not be reconciled, and added: "You can't have a one-person conspiracy."
Col Pohl told the court: "The plea deal is cancelled."
The judge had repeatedly warned Pte England's legal team that testimony meant as mitigation to reduce her sentence was implying her innocence.
"Both sides have indicated to me there is no way to resolve this inconsistency," he said on Wednesday.
Under military law, he could only accept the plea agreement if he was convinced that Pte England knew at the time that what she was doing was illegal.
New trial likely
Legal experts described Col Pohl's decision as a shock, but added that under military law the judge must protect the defendant and ensure that Pte England entered the plea agreement of her own free will.
The case now goes back to the commander of Fort Hood, Lt Gen Thomas Metz, who will decide whether to file new charges against Pte England and what those charges might be.
The process could take months, and experts said a new trial is likely.
However, it will be difficult for Pte England and her defence team to enter a new plea agreement.
Neither the prosecution nor the defence would comment on the turn of event, and the defence team shielded England from reporters.
On Tuesday, Graner passed a handwritten note to reporters saying he wanted Pte England to fight the charges.
"Knowing what happened in Iraq, it was very upsetting to see Lynn plead guilty to her charges," he wrote.
In January, Graner was found guilty on charges of assault, battery, dereliction of duty and the maltreatment of prisoners. He is serving a 10-year prison sentence.