A 33-year-old ex-Marine from Oklahoma is charged with murdering his stepfather, who authorities say suffocated after being the recipient of an "atomic wedgie."

Brad Lee Davis, 33, was arrested Tuesday on first-degree murder charges in the Dec. 21 death of his stepfather, 58-year-old Denver St. Clair, according to Oklahoma City television station KFOR.  According to the Oklahoman, Davis gave St. Clair an atomic wedgie – a maneuver that involves pulling a person’s underwear over and around their head.

Amy Elliot, a spokeswoman for the Oklahoma state medical examiner’s office, told the Oklahoman that Davis died from blunt force trauma to the head and asphyxiation. The death was ruled a homicide. Elliot told Tulsa television station KJRH that the asphyxiation was “caused by the elastic underwear band being stretched over his head and left around his neck.”

Davis allegedly told authorities that he gave his stepfather an atomic wedgie in self-defense. Davis claimed his stepfather struck him first and he fought back by giving St. Clair an atomic wedgie, KJRH reported.

According to investigators, Davis and St. Clair were drinking during the dispute in Pottawatomie County, and St. Clair allegedly spoke “ill of Davis’ mother.”

"We continued our investigation and uncovered evidence that led us to believe that this was more than just a fight," Pottawatomie County Sheriff Mike Booth told KJRH. Authorities told the station they believe Davis manipulated the crime scene to make it look like he acted in self-defense.

St. Clair’s ex-wife, Tressia St. Clair, took out an order of protection against him in 2008, the Oklahoman reported, citing Oklahoma Supreme Court records. She also filed for divorce against St. Clair in 2010 but the divorce was dismissed. She filed another divorce petition in 2012.