MILWAUKEE, Wis. – The gunman in Sunday’s Sikh temple shooting in the U.S. died of a self-inflicted gunshot wound to the head after he was shot by police, the FBI announced Wednesday.

FBI Special Agent in Charge Teresa Carlson told a news conference that investigators have not yet “clearly defined a motive” for the shooting at the Sikh Temple of Wisconsin that left six worshippers dead.

Authorities previously said an officer had fired the shot that killed gunman Wade Michael Page.

Authorities still haven’t identified anyone other than the gunman as being responsible for the attack.

Temple members have said the temple had never received any threats, and Page had not been seen at the temple in the past.

Carlson said federal officials had not opened any investigation into Page before the shooting. She said investigators were interviewing dozens of people who have known Page as they worked to determine for a possible motive.