An 18-year-old Michigan man now faces murder charges after the 64-year-old man he’s accused of brutally beating in a road-rage assault died from his injuries on Oct. 31, WOOD reported.

Prosecutors “enhanced” the charges against Christian William Hillman on Nov. 1 to include second-degree murder. He had originally been charged with assault with intent to commit great bodily harm. He’s also accused of being under the influence of marijuana at the time of his arrest.

William McFarlan was found lying on a Caledonia Township road with multiple face and rib fractures and bleeding on the brain, probable cause documents stated. One witness claimed to have seen Hillman kick a helpless McFarlan several times and then use an obscene taunt.

Hillman told deputies he acted in self-defense after McFarlan grabbed his neck, according to the probable cause document. Hillman said he had to “make sure [McFarlan] was completely immobilize so he didn’t hurt (him).” Police said Hillman claimed to be an ex-heavyweight boxer and admitted he “lost his [expletive].”

One witness told police he arrived at the scene when the assault had concluded and Hillman asked him to take a picture of his bloody hands. Police have said they’re in possession of that photo.

Hillman is jailed on $100,000 bond and has his next court appearance Dec. 1, WOOD reported.