CASPER, Wyo. (AP) — A man suspected of fatally shooting another man in Casper has pleaded not guilty to first-degree murder.

Prosecutors say 32-year-old Jason Tsosie John shot and killed 29-year-old Wesley Willow Jr., inside John's trailer on Aug. 3 after John got in an argument with Willow's then-girlfriend.

John told investigators that Willow, the woman and another man confronted him at his home. John says Willow charged at him and he shot Willow in self-defense.

John is charged with a single count of first-degree murder.

He pleaded not guilty Tuesday.

First-degree murder carries a penalty of life in prison or death.

Assistant District Attorney Trevor Schenk told District Judge Catherine Wilking during the Tuesday hearing that prosecutors will not seek the death penalty.