Four people were killed after two small planes collided in Phoenix, Ariz. The cause of the crash is unknown as of Friday 11 a.m. MST, and the investigation is ongoing.

The single-engine planes collided and went down around 10 a.m. Friday MST on New River Road in north Phoenix, Arizona Central reported. One of planes caught fire before crashing and the other aircraft, described as a Piper Archer, was mostly intact, the news outlet reported.

Initially, three people were declared dead and the fourth person was labeled missing. The Phoenix Fire Department confirmed the fourth fatality around 11 a.m. MST, reported.