STRATFORD, Conn. — A school bus driver here has been accused of using his bus to buy and deliver heroin, police said.

Garfield Howell, a bus driver for WE Transport who drives students in the Bridgeport Public Schools district, was identified by the Stratford Police Narcotics Vice and Intelligence Unit as a suspected heroin dealer and was placed under surveillance, NBC 4 reports.

Howell was reportedly seen using the school bus to purchase and deliver heroin several times during the course of the months-long investigation, police told NBC 4. Stratford Police Capt. Frank Eannotti told the news source that the suspected transactions were made after Howell dropped off all the students, and that no children were present when he dropped off or picked up drugs. Howell was arrested on Thursday, according to The Stratford Star. He faces charges of four counts of sale of a narcotic, two counts of conspiracy to sell narcotics, and risk of injury to a minor.

A manager from WE Transport’s local terminal in Bridgeport told NBC 4 that the company is investigating the allegations.