The Port Authority Police are trying to figure out who was behind a security breach at John F. Kennedy International Airport in December 2015.

A man was able to gain access to the tarmac at the airport on Decemebr 13, and the key questions now are who did this and how, WCBS 880’s Peter Haskell reported. It’s believed the man went over an eight-foot fence near Terminal 8. An airport employee questioned the intruder, who then ran off, Haskell reported. Air traffic was held for 45 minutes while police searched the area.

Port Authority Police report they’re questioning workers and reviewing security video, which shows a man climbing over the razor wire-topped fence. There are also questions about the response time.

Congressman Gregory Meeks met with the Port Authority officials about the incident. He believes they need to do better. “A number of police officers who are patrolling the perimeters of the airport, but it’s not enough,” Meeks said. Meeks is concerned about the intruders’ motive. The Port Authority declined to comment on the meeting.

According to the New York Post, there was a delayed response because a 911 call regarding the incident went to the NYPD, which then notified the Port Authority Police.

According to a report released earlier this year, the security perimeter at the JFK Airport has been breached at least four times in the past decade.