The Army has opened a new investigation into the friendly-fire death in Afghanistan of Pat Tillman (search), who quit the NFL to be a Ranger, officials said Monday.

Army officials said Tillman's family sought additional information about circumstances of his April 22 death, but the fundamental account of the battle in which he was killed is not being challenged.

"The family asked questions, and we're looking to get answers to the questions," said Army spokesman Paul Boyce. Officials declined to be more specific.

The Army's Special Operations Command, based at Fort Bragg, N.C., is conducting the investigation, said command spokeswoman Carol Darby.

Then-acting Army Secretary Les Brownlee (search) ordered the new investigation in mid-November based on the family's questions, Army officials said.

The results of the original Army investigation were released on May 29.

It found that Tillman was shot to death on April 22 after a U.S. soldier mistakenly fired on a friendly Afghan soldier in Tillman's unit, and other U.S. soldiers then fired in the same direction.

Initial reports by the Army had suggested that Tillman was killed by enemy gunfire when he led his team to help another group of ambushed soldiers.

Tillman, 27, left his position as a starting safety for the Arizona Cardinals (search) to join the Army after the Sept. 11, 2001, attacks. He was posthumously promoted from specialist to corporal and received posthumously a Purple Heart and Silver Star. The latter is among the military's highest honors, awarded for gallantry on the battlefield.

No soldiers faced judicial action as a result of his death, but several were disciplined, Darby said. One enlisted soldier faced formal administrative charges, and four more Rangers, including an officer, were transferred from the elite Ranger force to elsewhere in the Army. Two more officers were reprimanded, she said.

The military would not release additional details because the disciplinary actions were administrative, Darby said.