A medical transport jet with a child patient, her mother and four others aboard crashed into a Philadelphia neighborhood shortly after takeoff Friday evening, exploding in a fireball that engulfed several homes.

An eight-foot-deep crater left behind by from a medevac plane crash in North Philadelphia was filled in. Seven people, including six aboard the plane, were killed and dozens more were injured. Investigators are unsure what caused the Learjet to plummet from the sky less than a minute after takeoff.