clock menu more-arrow no yes

Filed under:

Police: Woman shoots, kills ex-husband's new girlfriend in Midvale

Chelsea Watrous Cook
Salt Lake County Jail

MIDVALE — Police have arrested a woman who they say shot and killed her ex-husband's girlfriend while delivering medicine to her young children.

Police say both children witnessed the killing and the chaos.

Chelsea Watrous Cook, 32, of Herriman, was booked into the Salt Lake County Jail Sunday for investigation of aggravated murder in the death of Lisa Vilate Williams, 26.

Cook was a health and yoga teacher at Skyridge High School in Lehi, according to the school's website and Cook's Facebook page. By midmorning Monday, Cook's profile had been removed from the high school's website. A spokesman for the Alpine School District said Cook was immediately fired.

The tragic incident unfolded just before 7 p.m. Sunday when Cook went to an apartment at 7690 S. Center Square to drop off cold medicine to one of her children. Cook went into the apartment while her ex-husband was in the parking lot.

"(Cook) was told to leave the apartment, but she refused to listen. (She) remained unlawfully inside of the apartment during this time. (She) then locked herself in the bathroom while (she) was on the phone with the 911 operator," a Salt Lake County Jail report states.

Cook then came out of the bathroom, walked to her coat, grabbed a handgun and fired three to five rounds at Williams, according to the report.

The ex-husband, who had by that point come back into the apartment, grabbed the gun from Cook and attempted to give first aid to his girlfriend, police say.

"(Cook) then walked over to their children and sat on the recliner chair," the report states.

When Cook got up to get her coat and leave, her ex-husband pinned her against a wall until officers arrived.

Williams was shot at least twice in the torso, according to police. She died from her injuries at a local hospital a short time later.

The couple's twins, both 3, were "present during the entire ordeal," the report states.

Unified police originally responded to the scene to investigate, but due to a "conflict of interest," Salt Lake police were called to take over the investigation. One of the people involved in the incident is related to a Unified police employee, investigators confirmed.

According to court records, Cook was charged with assault and two counts of domestic violence in the presence of children, all misdemeanors, last month for an incident on Oct. 16. According to Herriman police, she caused minor injuries to an adult male at her apartment. The man, who police did not identify, did not require treatment at a hospital, according to police. Her next court date in that case is scheduled for Dec. 18.

Cook worked for the Alpine School District for four years, first with Lehi High, then with Skyridge High when it opened in 2016, according to the district.

"We’re obviously devastated by the news we heard this morning. Our thoughts are with all those who have been impacted by this situation,” said district spokesman David Stephenson, who called the incident a "horrific situation."

Counselors were at the school Monday for any students or faculty members who needed them.

Skyridge Principal Joel Perkins sent a letter to all parents Monday, encouraging them to read it to their children immediately. In a second letter Monday afternoon, Perkins addressed concerned parents who wondered why no action was taken after Cook's Oct. 16 arrest.

"We were unaware of any previous charges as we have not been notified through the established process," the second letter says.

"This type of news is hard to comprehend and we want you to know that teachers, counselors and your parents can help provide support in this difficult time," the first letter says.

The letter also attempts to discourage parents and students from speaking to the media about their opinions or thoughts.

Free and confidential help and support for victims and survivors of domestic violence is available 24/7 at 1-800-897-LINK (5465) or visiting