The Massachusetts D-A helped catch a suspect yesterday.
He joined a host of patrons at a Falmouth restaurant chasing a man, after a woman screamed that he had snatched her purse.
Keating is a former track team captain and says he shifted into another gear chasing the bad guy.
Keating adds he didn't know he still had it in him.
The man was arrested and the purse returned.
Keating is running in tomorrow's Democratic primary for an open congressional seat.