Authorities are investigating how a stun gun made it past security and onto a plane.

A cleaning crew found a stun gun in the seat pocket of a Jet Blue plane in Newark, N.J., after it had just arrived from Boston Friday night.

Port Authority spokesman Steve Coleman told the Associated Press it's not clear who the weapon belonged to or how it got on the plane.

Coleman says there's no indication the weapon had been fired.

The stun gun was turned over to the Transportation Security Administration, the agency who's responsible for screening those who boarded the flight.

The FBI is also involved in the investigation.