Police arrested a man who tried to board an airplane with a pocketknife in his shoe Wednesday at the Dane County Regional Airport.

Gregory D. Roberts of Massachusetts was charged with a felony for attempting to board the plane with the knife in the first such security incident at the Dane County Airport since the Sept. 11 terrorist attacks prompted increased airport-security measures.

Roberts reportedly told security officers he placed the knife in his shoe when he realized it would probably be confiscated by security personnel. He said the knife was a family heirloom.

Airport officials discovered the knife in Roberts’ shoe when he passed through the airport’s metal detector.

Assistant U.S. Attorney John Vaudreuil told the Associated Press no evidence existed to suggest Roberts intended to harm anyone or that he was connected with any sort of terrorist plot.

“It was the wrong time to be doing this sort of thing,” Vaudreuil said. “We definitely treat this very seriously.”

Magistrate Judge Stephen Crocker released Roberts Wednesday afternoon on the condition he returns for court appearances.

Roberts’ charge carries a maximum penalty of 10 years in prison and a $250,000 fine.

Deputy airport director Rod McLean was unavailable for comment on the incident.