ROCKLAND (AP) – The Knox County Regional Airport has taken steps to boost security while an investigation continues into how a box cutter ended up on a plane that had departed from the airport.

Additional roving patrols are being made inside and outside the perimeter to check for suspicious activity, said airport manager Greg Grotton.

Grotton said he hoped to have more information Thursday about the box cutter on US Airways Express Flight 4971. The discovery was made Tuesday night by a flight crew at Logan International Airport in Boston.

On Wednesday, Grotton said he had little information. “The FBI is here and is doing some investigating,” he said.

According to Grotton, the plane had made several stops before coming to Maine. It originated in Hyannis, Mass., on Cape Cod, and stopped in Boston to pick up passengers before coming to Owl’s Head.

Those passengers were dropped off and another four customers boarded the plane for a return trip to Boston.

The retractable utility knife and a “single-edge razor blade” were found in a seat-back pocket of the airplane while at Logan, said Ann Davis, spokeswoman for the Transportation Security Administration in Boston.

The TSA would not speculate on how the knife got onto the airplane, but that type of tool is “commonly used by maintenance workers,” she said.

After the Sept. 11, 2001 terrorist attacks, a full-time security coordinator was hired as well as four part-time security officers, all of whom are certified by the Knox County Sheriff’s Department, Grotton said.

All airplanes are inspected by airport security staff each morning and at the end of the day, he said.

The airport has one security checkpoint, or metal detector, through which passengers must pass, and the TSA has seven full- or part-time screeners assigned to the airport, Davis added.