SALT LAKE CITY — A Utah teacher accused of gunning down her ex-husband's new girlfriend in front of their twin children was charged Wednesday with aggravated murder. 
 
 Chelsea Watrous Cook, 32, of Herriman, could face the death penalty for the first-degree felony in the shooting death of 26-year-old Lisa Vilate Williams. 
 
 Cook is also charged in 3rd District Court with a first-degree felony charge of aggravated burglary and three counts of felony discharge of a firearm — one first-degree felony, one second-degree felony and one third-degree felony — as well as two counts of committing a violent offense in the presence of a child, a class B misdemeanor. 
 
 Cook had gone to her ex-husband's home, 7690 S. Center Square, Midvale, on Nov. 25 under the pretense of dropping off cold medicine for one the 3-year-old twin sons they shared, police said. When her ex-husband walked out of his apartment to meet her in the parking lot, Cook, who was seen in security footage waiting in the hallway, slipped through the unlocked door into the apartment, according to the charges. 
 
 Not seeing Cook in the parking lot, the ex-husband returned to his apartment where he found Cook in the living room with Williams and the children, charges state. 
 
 Cook was told numerous times to leave but refused, according to the charges. Instead, when her ex-husband picked up the phone to call 911, she walked to the bathroom and locked the door behind her. 
 
 "Approximately 15 seconds later, Cook came out of the bathroom and walked toward her coat," charges state. Cook's ex-husband, who was standing behind her, "heard multiple gunshots and saw Cook pointing a gun at Ms. Williams." 
 
 Cook's ex-husband grabbed the gun away from her and she went and sat down with the two children, who had witnessed the shooting, according to the charges. Once her ex-husband was back on the phone with 911, Cook moved again toward her coat. 
 
 "Unsure if Cook had another gun hidden in her coat, (her ex-husband) pinned Cook up against the wall until officers arrived" and told the two children to go to their bedroom and lock the door, charges state. 
 
 Williams was shot once in the chest, once in the hip and once in the back, charges state. 
 
 Williams' mother, Tawny Williams, told the Associate Press that Cook had been harassing her daughter leading up the shooting. 
 
 Cook was a health and yoga teacher at Skyridge High School in Lehi, according to the school's website and Cook's Facebook page. A day after the shooting, Cook's profile had been removed from the high school's website. A spokesman for the Alpine School District said Cook was immediately fired. 
 
 Cook remains in Salt Lake County Jail without bail. An initial court date had not been scheduled Wednesday. 

 This undated photo provided by the Salt Lake County Sheriff's Office shows Chelsea Watrous Cook. Police say Cook, a Utah high school teacher, shot and killed her ex-husband's girlfriend while the former... (Associated Press) 
 
 This undated photo provided by the Salt Lake County Sheriff's Office shows Chelsea Watrous Cook. Police say Cook, a Utah high school teacher, shot and killed her ex-husband's girlfriend while the former couple's children looked on. (Salt Lake County Sheriff's Office via AP) (Associated Press) 
 
 This undated photo provided by the Salt Lake County Sheriff's Office shows Chelsea Watrous Cook. Police say Cook, a Utah high school teacher, shot and killed her ex-husband's girlfriend while the former couple's children looked on. (Salt Lake County Sheriff's Office via AP) (Associated Press) This undated photo provided by the Salt Lake County Sheriff's Office shows Chelsea Watrous Cook. Police say Cook, a Utah high school teacher, shot and killed her ex-husband's girlfriend while the former... (Associated Press) 
 
 SALT LAKE CITY (AP) — The Latest on the killing of a Utah woman in front of her children (all times local): 
 
 8:30 p.m. 
 
 The family of a Utah woman who authorities say was killed by her boyfriend's ex-wife while decorating a Christmas tree is warning about the devastating consequences of domestic violence that go beyond two people. 
 
 Police say 26-year-old Lisa Vilate Williams was making homemade ornaments with her boyfriend's twin 3-year-olds when 32-year-old Chelsea Watrous Cook burst in and shot her to death on Sunday. 
 
 Cook was arrested on suspicion of aggravated murder after her ex-husband took the gun away and pinned her to the wall until police arrived, authorities said. 
 
 Williams' sister and mother told The Associated Press that the slaying came after Cook bullied Williams online and harassed her for months. 
 
 Court records show Cook had been charged with domestic violence the month before the slaying. 
 
 A lawyer for Cook in that case did not return messages seeking comment, and family members declined to comment. 

 In this undated photo provided by Tawny Williams shows Lisa Vilate Williams. The family of a woman killed by her boyfriend's ex-wife while decorating a Christmas tree is sounding a warning about the devastating... (Associated Press) 
 
 In this undated photo provided by Tawny Williams shows Lisa Vilate Williams. The family of a woman killed by her boyfriend's ex-wife while decorating a Christmas tree is sounding a warning about the devastating consequences of domestic violence that goes beyond two people. Police say 26-year-old Lisa... (Associated Press) 
 
 SALT LAKE CITY (AP) — A woman drew her ex-husband outside his apartment with a message about dropping off cold medicine for their 3-year-old twins, then sneaked inside and fatally shot his girlfriend while she and the children were decorating a Christmas tree, a Utah prosecutor said Wednesday. 
 
 Chelsea Watrous Cook is charged with aggravated murder, burglary and violence in the presence of a child in the killing of Lisa Vilate Williams. No attorney was immediately listed in court records for Cook, who was a high school heath teacher in Lehi, Utah, before her arrest on Nov. 25. 
 
 Cook, 32, refused to leave when her ex-husband, Travis Cook, returned from the parking lot, authorities said. She locked herself in the bathroom as he called 911. 
 
 Less than a minute later, she walked out and grabbed a gun from her coat and fired the fatal shots. Her ex-husband told the children to run into their rooms and lock the doors. He pinned his ex-wife to the wall and waited for police to arrive. 
 
 Williams' family has said Cook harassed the 26-year-old woman for months online, on the phone and in person before the shooting. A police report indicates Williams had come up during a previous fight between the onetime couple the month before she was killed. 
 
 The report detailing misdemeanor domestic-violence charges filed against Cook was obtained by The Associated Press under a public-records request. 
 
 It said the couple had a history of difficult custody exchanges, and on Oct. 16 Cook yelled "disparaging comments" about Williams during an unrelated fight as her ex-husband tried to pick up the children. 
 
 When he prompted one of the children to say they were excited about seeing her, Cook got angry and grabbed the man by the hair, sending him tumbling down the stairs, police said. Williams was not present at the time. 
 
 Her lawyer in that case has not returned calls seeking comment, but Cook had pleaded not guilty.
– Utah has never executed a woman or had a woman on death row, but that could change after Sunday night's murder in suburban Salt Lake City. Chelsea Watrous Cook, 32, has been charged with aggravated murder in the shooting of Lisa Vilate Williams, 26, and could face the death penalty, Deseret News reports. Police say the teacher lured ex-husband Travis Cook out of his apartment by saying she had cold medicine for one of their 3-year-twins, reports the AP. Security camera footage captured her hiding in the hallway as he walked out to the parking lot. Police say she then sneaked into the apartment, where she ended up shooting Williams, her ex-husband's new girlfriend, who had been making Christmas tree ornaments with the twins. Authorities say Travis Cook managed to get the gun away from his ex-wife and pin her to a wall until police arrived. Williams' mother and sister tell the AP that they feared for her safety after Cook harassed her and bullied her online for months. Public records state that Cook was charged with misdemeanor domestic violence last month after arguing with her ex-husband when he tried to pick up the twins. Court records state that she yelled "disparaging comments" about Williams, who was not present, and grabbed her ex-husband by the hair, causing him to tumble down stairs. Cook, who worked as a health and yoga teacher at a Lehi high school, is being held without bail.