HARRISBURG, Pa. (CBS) — At least three Pennsylvania Senate employees have been fired after a heroin bust in a Senate mail facility in Harrisburg.

Two arrests were made last week at the Pennsylvania Senate mail facility, which is not located in the state capitol complex. And Drew Crompton, a top aide to the top ranking senator, says in addition to the two arrested, at least one more employee has been fired following interviews. Crompton says he’s disappointed by the employees’ actions but pleased with the way it was handled.

“We have employees, just like everyone else has employees,” Crompton said. “They’re real live human beings, they make their own decisions, even if they’re bad ones.”

Crompton says a supervisor immediately called police when he suspected a drug transaction. Packets found in a Senate mail facility rest room turned out to be heroin.

Crompton says extra surveillance cameras were added and employees were warned after odd behavior was observed at the facility several months ago.