Atlanta police shot Donald Hamilton, 31, in the head and in his arms and legs early Sunday after witnesses reported that he was waving a gun while walking down Peachtree Road, authorities said.

Officers opened fire on Hamilton when he turned and pointed a handgun at them, rather than complying with orders to put the gun down, police said.

Hamilton was identified on Monday.

Three officers were involved, though it's not clear whether all opened fire. Police did not release their names Monday, but said two have been with the department for more than seven years and the third is a one-year veteran.

In addition to the gun that Hamilton had in his hand, police also found another handgun in his waistband.

Medical officials also discovered a pocketknife in the cleft of Hamilton's buttocks during an autopsy, said Mark Guilbeau, an investigator with the Fulton County Medical Examiner's office.

Guilbeau said the knife was not attached to Hamilton but was held in his buttocks by "friction."

Lt. Keith Meadows, commander of the police department's homicide unit, said it's possible Hamilton wanted police officers to shoot him — an act called 'suicide by cop.'

Witnesses who saw Hamilton waving the gun told police he did not have any prior confrontations with anyone, Meadows said.