The White House says President Barack Obama and British Prime Minister David Cameron agree their nations must investigate what happened during an American rescue attempt in which a captive British aid worker was killed in Afghanistan.
The U.S.-led NATO coalition says that U.S. forces may have detonated a grenade that killed Linda Norgrove during the operation to free her.
Norgrove died Friday night _ nearly two weeks after being captured _ when U.S. special forces stormed the Taliban compound where she was being held.
The White House says Obama called Cameron to offer condolences. Officials say that Obama and Cameron both agreed the rescue operation was necessary and it was essential to "get to the bottom" of what happened in the rescue attempt.