OWLS HEAD – FBI agents departed Thursday after interviewing staff at Knox County Regional Airport as part of their investigation into the discovery of a knife on a US Airways Express plane.

The retractable knife and a razor blade that may have been used with it were found in a seat-back pocket on the plane at Logan Airport in Boston on Tuesday night.

The flight originated in Hyannis, Mass., but included a stop at Owls Head.

Airport manager Greg Grotton had no new information about the investigation on Thursday.

“At this point in time, it is out of my hands,” he said.

FBI agents did not recommend any changes to procedures at the airport or shed any light on whether the knife had been placed on the plane in Maine.

“It’s something no one wants to see at their airport,” Grotton said of the knife incident. “It’s something no one wants to see, period.”