Cook came to her ex-husband’s Salt Lake City apartment on Sunday night to give one of their three-year-old twins cold medicine but refused to leave 

A Utah high school teacher has been arrested for allegedly shooting and killing her ex-husband’s girlfriend in front of the former couple’s twin daughters.
Police said Chelsea Watrous Cook, went to her ex-husband’s Salt Lake City apartment on Sunday night to give one of their three-year-old twins cold medicine.
Cook allegedly locked herself in a bathroom when her ex-husband Travis Cook asked her to leave. She eventually came out of the bathroom and grabbed a gun from her coat, according to police.
Cook then allegedly fired the gun five times at 26-year-old Lisa Vilate Williams while her daughters were watching.
The victim was shot twice in the torso and fell back onto the couch.
Her ex-husband told police that Cook sat in a recliner chair near their daughters and watched as he tried to help his injured girlfriend.
When she got up and tried to get her coat, her ex-husband pinned her to a wall until police arrived.

Cook, who was arrested on suspicion of aggravated murder, taught health class at Skyridge High School.
She is also currently facing separate domestic violence charges related to an incident in October to which she has pled not guilty.
The charging documents in that case are sealed but it is related to abuse in front of children. She was accused of causing minor injuries to a male at her apartment. The man was not identified by police, and his relationship to Cook was also not disclosed, the newspaper reports. The victim did not require treatment at the hospital. Her next court appearance in that case is scheduled for December.