A Decatur man accused of punching a 14-year-old girl in the face for running into his son on the slopes in Colorado has pleaded guilty to third-degree assault.

The Vail Daily reported Tuesday that the plea from 41-year-old Scott Filler, a renowned malaria expert, was for a misdemeanor stemming from the December incident at Beaver Creek Ski Resort.

Police reports say Filler thought the teen was skiing carelessly when she bumped into his 4-year-old son. Eagle County sheriff's deputies say that's when he jumped on the girl and hit her with his fist. The girl said she was swerving to avoid another skier.

District Attorney Mark Hurlbert says Filler was sentenced to anger management classes and restitution, the amount of which would be determined by the girl.

Prosecutors also sought community service, but Hurlbert says the judge fined Filler $500 instead.

Three witnesses told deputies they observed Filler punch girl between two and four times.

The ski instructor who pulled the Decatur man off the girl told deputies Filler punched her "at least four times, using a closed fist," sheriff's Lt. Mike McWilliam told the AJC. Two other witnesses said they observed Filler yell at the girl before landing two or three punches, the sheriff's office spokesman said.

Filler, charged with misdemeanor child abuse, told deputies he thought the girl was skiing carelessly and had seriously injured his son. The boy was not hurt, however, and Filler apologized. The girl was treated for minor injuries at a local medical center.

Her father requested charges be filed against Filler, who was banned for life from Vail's six ski resorts.

Filler's work as a "disease detective" with the Epidemic Intelligence Service was chronicled in former AJC reporter Maryn McKenna's book, "Beating Back the Devil."

The Associated Press and AJC reporter Christian Boone contributed to this article.