"This is one of the worst cases I've ever seen and been a part of," said the homicide detective.
A 27-year-old mother who beheaded her five-year-old daughter was sentenced to life in prison on Thursday.
Krystle Villanueva was arrested on January 5, 2017, after authorities arrived to her home in Austin, Texas to find she had stabbed little Giovanna Hernandez to death and decapitated her, according to the Austin American-Statesman.
The police were first notified by Villanueva's father-in-law, who was stabbed in the head and back by Villanueva, but managed to escape and run out of the house to call 911. As officers surrounded the home, Villanueva also called 911 and told the operator she had killed her daughter because "she asked for cereal," per the news outlet.
When a SWAT team broke down the door in an attempt to save Giovanna, they found Villanueva freshly showered and naked in the front room, according to the police report. Giovanna was found "stabbed and decapitated" in her bedroom.
"I've been in this line of work for over 43 years — 11 years as a homicide detective," Hays County Sheriff Gary Cutler told the newspaper at the time. "This is one of the worst cases I've ever seen and been a part of."
Villanueva's conviction of capital murder comes after a two-week trial, where her lawyers argued she was not guilty by reason of insanity.
"Ms. Villanueva claimed that, at the time of the attacks, she had been under the delusional belief that her daughter and her father-in-law had been replaced by clones and had to be killed to bring back her real family members," Hays County District Attorney Wes Mau said in a statement.
"While evidence indicated that Ms. Villanueva had been treated previously for mental problems, the prosecution pointed out that all such treatment coincided with prior drug abuse."
At the time of the arrest, blood testing revealed the presence of alcohol and marijuana in Villanueva's system, according to the police report.
"A case like this leaves an unforgettable mark on everyone involved, especially the child's family," Mau said in a statement. "Every law enforcement member who worked on this case will forever be traumatized by what Ms. Villanueva did to her innocent daughter."
"I commend all the investigators and officers who endured this horror with calm professionalism so that justice could be done," he added.