Copter on quake mission flips in Mexico, kills 13 on ground

A downed helicopter lies on its side on top of a van, in Santiago Jimitepec, Oaxaca state, Mexico, Saturday. (Luis Alberto Cruz Hernandez/AP Photo)

MEXICO CITY — A military helicopter carrying officials who were assessing damage from a powerful earthquake flipped as it was attempting to land in southern Mexico, crashing on top of people who had fled their homes and were spending the night outside. Thirteen people were killed — the only known fatalities related to the quake — and 16 were injured.