BOULDER — A former police officer who shot and killed an elk while on duty is going on trial in Boulder.

Thirty-seven-year-old Sam Carter says he shot the animal because it was injured but investigators say there was no sign that it was hurt before it was killed.

Lawyers will begin selecting jurors Tuesday. They will determine whether the killing on New Year's Day 2013 was criminal.

Another police officer who helped Carter, Brent Curnow, pleaded guilty to one felony and four misdemeanor charges and was sentenced in September to one year of probation and two months of house arrest.