CHATTANOOGA, Tenn. — A school bus driver was behind bars Tuesday after a crash killed five youngsters and plunged Chattanooga into mourning over what the mayor called the “most unnatural thing in the world” — a parent losing a child.

Police said Johnthony Walker, 24, was speeding along a winding road Monday afternoon with 35 elementary school students aboard when he wrapped the bus around a tree.

Walker was arrested and charged with five counts of vehicular homicide.

Residents made a memorial of flowers and toys at the crash site and held a prayer vigil.