A Stockton, Calif., man was arrested late Monday night as he tried to rob the Valero gas station in the 8800 block of Jewella Avenue about 11:20 p.m.
Derek Pierson Jr., 21, entered the store with a mask covering his face and demanded money, police spokeswoman Kacee Hargrave said.
But Agent L.J. Scott, a member of the Shreveport Police Department Armed Robbery Task Force, was also in the store, dressed in his police uniform.
Scott ordered Pierson to show his hands and he obeyed. Scott then took the man's handgun from him and arrested him.
Pierson has been charged with armed robbery with a firearm and booked into the Shreveport City Jail.