NASHVILLE, Tenn. (AP) — Students and administrators raised concerns about a Tennessee school bus driver’s behavior behind the wheel in the weeks before a crash killed six children.

Police have charged the driver Johnthony Walker with vehicular homicide after the Chattanooga crash. Federal authorities said Walker was driving off the designated bus route when he wrecked on a curvy road while carrying 37 children on their way home from Woodmore Elementary School.

Records released by the school district on Friday include two written statements by students complaining about Walker’s driving. One said the driver would stop the bus to make students moving from their seats hit their heads. Another wrote: “We need seat belts.”

The school’s principal asked for video of the bus leaving campus, saying that in her opinion he was “driving way too fast.”