Attorneys for Lynndie England, the Army private who became the public face of prisoner abuse at Iraq’s Abu Ghraib prison, said Thursday that she would plead not guilty when the Army reopens her court-martial later this summer on charges of mistreating Iraqi prisoners. Earlier this year, the 22-year-old had agreed to plead guilty to several charges in return for reduced prison time. But an Army judge threw out her plea in May, saying the confession she had worked out with Army prosecutors was not believable.