The Australian pilot who died in a Melbourne plane crash on Tuesday, along with four U.S. citizens, had been previously investigated. Authorities said Max Quartermain was investigated over a "near collision" crash in September 2015. Quartermain and four other passengers died after their light aircraft crashed into a mall rooftop due to engine failure. Quatermain, who is an experienced pilot, took off from Melbourne's small Essendon Airport right before issuing two mayday calls. The national transport safety board said they won't be "participating in any speculation" over the incident.