Edmonson said troopers were on the way to the scene in Sunset, about 60 miles west of Baton Rouge, after getting a call around 4:45 p.m. Wednesday.
Edmonson says the shooting reportedly took place near a convenience store. He says the officer was "responsive" but he has no details on the extent of the officer's injuries - or those of the other two people who were stabbed.
Tonette Thibodeaux of the Sunset police department confirms that an officer was shot but says she does not have any details.
The suspect has barricaded himself inside the store. After negotiations attempts and tear gas failed to get the suspect to surrender, officers broke down the door and took him into custody. The suspect was taken to a hospital to seek treatment for irritation resulting from the tear gas.
Sunset is a town of about 2,900 in St. Landry Parish, 13 miles north of Lafayette.
The police department consists of Chief Louie Padilla, six officers, four dispatchers, a secretary and 12 reserve officers, according to the department's website.