GASCONADE Co., Mo. -

A Jefferson City man pleaded guilty in Gasconade County court Friday for the deaths of two and injury of three people in a September 2011 boating accident.

Winkler was charged with two counts of involuntary manslaughter and two counts of second degree assault. He pleaded guilty to one count of involuntary manslaughter, and the other was dropped at the request of one of the victim's families. Winkler also pleaded guilty to both assault charges. 

35-year-old Christopher Winkler was driving his boat at night along the Osage River in Osage County when it hit two anchored boats at the Bonnots Mill river access.

Authorities said Winkler was operating the boat without required life jackets.

Curtis Libbert and Alvin Blackford died in the accident.