FORT HOOD, Texas — The Fort Hood soldier suspected of killing three people and wounding 16 others last week began his eight-minute rampage on the sprawling Texas Army post after an argument related to taking leave, military investigators said Monday.

Army spokesman Chris Grey didn’t indicate during a brief news conference whether Spc. Ivan Lopez was granted the leave or the circumstances behind the request. The shooting spree Wednesday ended when Lopez killed himself with his .45-caliber pistol after confronting a female military police officer, who Grey said fired once at Lopez but didn’t strike him.

A spokesman for Lopez’s family said last week that Lopez was upset he was granted only a 24-hour leave to attend his mother’s funeral in November. That leave was then extended to two days.

Providing the most detail yet about the second mass shooting at Fort Hood in five years, Grey mapped out how Lopez opened fire in the building where the argument began before leaving and driving away, shooting at times from his car. The three who died were gunned down in separate locations.