A substitute teacher was arrested Thursday after students reported watching him use what appeared to be cocaine during a seventh-grade science class, authorities said.

Terry John Kappila, 45, of Jacksonville, was charged with felony cocaine possession. He was being held at Duval County jail. Twenty-two students allegedly saw Kappila sniffing a white powder at a computer desk during class, police told The Florida Times-Union for its Friday editions.

Two of the students left the classroom to report the alleged drug use, Lake Shore Middle School Principal Iranetta Wright said. "They said, 'Miss Wright, he is doing something wrong in there,"' Wright told the newspaper. "The students were very alarmed."

Kappila initially told authorities he had been mixing headache powders with coffee, but started inhaling the powders when he couldn't find the cup, according to a police report. He told police it was cocaine after authorities found a bag of powder at his feet while he was being questioned, the report stated. The powder in the bag tested positive for cocaine, police said.