Deputies arrested Harold Duane Poole and charged him with murder. Poole is a Drug Enforcement Agent, the sheriff says.
The incident happened in the 1700 block of Rhymes Road near Crystal Springs.
Investigators say Poole called 9-1-1 about a man trespassing on his property.
When deputies arrived on the scene, they discovered the body of Chase Brewer, 47.
Poole is awaiting his initial court appearance, but investigators are tight-lipped about any other details in the case.
The Mississippi Bureau of Investigation is assisting Copiah County deputies with this investigation.