A $10,000 reward was offered for information leading to the capture of the shooter, The (New Orleans) Times-Picayune reported.
Officer John Passaro was shot as he responded to a call about an armed robbery at a Dollar General store just before 7 a.m. Saturday.
He found no one inside the store and approached the closed door of the manager's office, where the gunman had ordered three employees to open two safes, investigators said.
When Passaro announced himself as a police officer, the gunman opened the door and fired three shots, hitting Passaro twice, they said.
The man then fled.
The officer was in intensive care in a hospital, the report said.