The truck driver who authorities say caused a highway crash outside Chattanooga in June, killing six, has been charged with vehicular homicide.

Multiple media outlets report that a Hamilton County grand jury on Monday indicted 39-year-old Benjamin Brewer of London, Kentucky, on six counts of vehicular homicide. The grand jury also indicted him on four counts of reckless aggravated assault, driving under the influence of narcotics, speeding and making false reports about his duty status. Chattanooga police issued an order for Brewer's arrest Monday.

According to a preliminary report released by the National Transportation Safety Board, Brewer had been on duty for about 50 consecutive hours in the three days leading up to the June 25 crash.

According to the Federal Motor Carrier Safety Administration, Brewer tested positive for methamphetamine six weeks before the crash.