Mayor Cherelle Parker said five people are still hospitalized following a fatal medical jet crash in Northeast Philadelphia, three of whom are in critical condition.

The Learjet, carrying a pediatric patient and five others, crashed on Friday, killing all on board. On the ground, one person was killed and at least 19 others were injured, officials said.

The plane crashed after less than a minute of flight, investigators determined, but they couldn't say yet why the jet plummeted to the ground.