BOSTON (CBS) – A veteran MBTA police officer is facing disciplinary action for falling asleep on the job.

A user on Twitter snapped a photo of the Transit Police officer asleep at the Mattapan MBTA station.

When confronted, the officer admitted falling asleep.

The man, who was not identified, is a 29-year veteran of the force.

“The performance of the officer is certainly a concern,” says Deputy Chief Joseph O’Connor. “Our officers are not supposed to be conducting themselves in that manner, we’re not going to tolerate it, and we will take appropriate action.”