BOISE, Idaho (AP) -- A Boise man accused of killing a friend with a punch to the face has been charged with second-degree murder.

Ada County Prosecutors amended the criminal charge this week against 26-year-old Joshua Luman.

Luman was initially charged with second-degree murder, but prosecutors changed it days later to involuntary manslaughter. Police say Luman punched 26-year-old Noah Hopper while they were drinking near a bandshell at a Boise city park on Sept. 7.

After being hit, police say Hopper fell and hit his head, and died the next day after being taken to a Boise hospital.

Deputy County Attorney Barbara Duggan has not yet revealed details that prompted her to charge Luman with a more serious crime. If convicted, Luman faces up to life in prison.

(Copyright 2009 by The Associated Press. All Rights Reserved.)