Investigators are still trying to determine the cause of a San Diego plane crash that left at least three people dead and several others injured in the military housing neighborhood of Murphy Canyon on Thursday.

Dense fog had rolled into the area around the time the plane was approaching the airport. Visibility was at half a mile at 3:55 a.m. and had dropped to a quarter of a mile just after 4 a.m. in the area around Marine Corps Air Station Miramar, which is just a few miles north of the crash site, according to the National Weather Service.

All six on the plane are believed to be dead, including a former drummer for The Devil Wears Prada and a high-profile music agent.