A person in a car was the seventh fatal victim of the fiery crash of an air ambulance onto a busy Philadelphia street, authorities said Saturday, as investigators sifted through burned cars, damaged homes and charred debris for clues to determine why the aircraft plummeted shortly after takeoff.

Jet Rescue Air Ambulance said it was unlikely anyone on board survived the Friday crash. Nineteen people on the ground were injured, Philadelphia Mayor Cherelle Parker said.

The plane had been on a medical transportation mission to Mexico, carrying a child patient, her mother and four crew members.