A Flathead Valley man arrested after allegedly injuring his infant child during a Christmas Eve argument with his girlfriend earned a deferred sentence in Flathead County District Court last month.

Judge Dan Wilson handed down the deferred three-year sentence for felony criminal endangerment to Joseph Richard Riggs, 39, on Sept. 21. Although pleading not guilty to the charge at his January arraignment, Riggs reached a deal with prosecutors in mid-June.

Wilson also gave Riggs 17 days of credit for time served.

Flathead County Sheriff’s Office deputies arrested Riggs after responding to a 911 hangup originating in a home on Montana 40 near Columbia Falls, court documents said. Riggs’ girlfriend later told authorities that the two argued after Riggs became drunk, court documents said.

Preparing to leave, she put the couple’s one-month-old in a car seat, but left the child unstrapped. Riggs, apparently trying to slow them down, allegedly grabbed the car seat and sent the child tumbling out of it.

The infant subsequently struck his head on a propane tank, court documents said. A CT scan determined the child suffered a subdural hematoma, or bleeding in the head, according to court documents.

News Editor Derrick Perkins can be reached at 758-4430 or [email protected].