BOULDER, Colo. -- A Niwot, Colo., woman stabbed two men in a three-way sexual encounter gone wrong, according to a Boulder County Sheriff's report obtained Wednesday.

Serena Brooks, 30, faces assault charges of stabbing her boyfriend and another man. Investigators said Brooks' boyfriend, Ruffin Griffin, 28, brought another man home from a bar late Monday night, then the two men became engaged in a sexual encounter with Brooks.

Police said that Griffin and Clint Cadigan, 27, then started fighting, ending up on the floor and continuing to fight. Police said Brooks grabbed a nearby knife to break up the fight and stabbed both men in the back.

Griffin and Cadigan then drove to the hospital together to seek treatment for their wounds early Tuesday morning. Both sustained serious but not life-threatening injuries, according to the sheriff's office.

"It is believed that alcohol and drugs were a contributing factor to the incident," said Boulder County Sheriff's Cmdr. Rick Brough. "There is a possibility that additional charges could be pursued."

Brooks was booked on investigation of two counts of first-degree felony assault and one count of misdemeanor child abuse. Police said the child abuse charge was filed because her and Griffin's 6-month-old son was in the home at the time.