Kylr Yust, 29, faces two counts each of first-degree murder and abandonment of a corpse in the deaths of Jessica Runions and Kara Kopetsky, according to Cass County, Missouri, jail officials. He was reportedly charged on Thursday.
Runions, 21, was last seen leaving a friend’s house party in September 2016. She allegedly left the party with Yust, a friend of her boyfriend.
Days after she vanished, Yust was arrested for allegedly burning Runions’ vehicle, which was found after she went missing, according to police in Kansas City, Missouri. That case has since been dropped in light of the murder counts, according to local TV station WDAF.
It was not immediately clear what led to the newly upgraded charges against Yust, who has been in custody since his arrest. The remains of both Kopetsky and Runions were found earlier this year.
Prosecutors and court officials could not be reached for comment on Monday.
Authorities alleged in a probable cause statement released Thursday that Yust confessed to choking Kopetsky to death after she said she wanted to end their on-again-off-again relationship, according to the Associated Press and CBS News.
According to one witness account in the statement:
“[The witness] stated Yost then told him the victim [Kopetsky] wouldn’t love him and that he was angry with her because he didn’t want her to love someone else. Yust then told [the witness] that he had just snapped, and that something bad happened to the victim.”
The probable cause statement reportedly claims that Yust confessed to a friend that he killed Runions in a similar manner last year, strangling her before taking her body into the woods.
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Kopetsky and Yust dated for nine months in 2007, when they were both teenagers, her mother said.
Days before she went missing, Kopetsky filed a restraining order against Yust, alleging he was violent towards her, according to a Cass County official.
Kopetsky was last seen leaving her high school in Belton, Missouri, during a free period on May 4, 2007. She was never seen or heard from again. She was 17 years old.
Her remains were found in April, in a rock quarry about nine miles from the school, about 20 to 30 yards away from where Runions’ remains were discovered.
“It has been a long 10 years and a long four months, and we finally found her and she is back where she belongs and we can finally put her to rest,” Kara’s mother, Rhonda Beckford, previously PEOPLE. “The next step is going to be properly laying her to rest and looking onward to a prosecution.”
A History of Violence
Since his Kopetsky’s disappearance, Yust’s violent behavior has landed him in court, according to documents obtained by PEOPLE.
In September 2011, Yust pleaded guilty to domestic violence after choking and striking his then-pregnant 18-year-old girlfriend, according to a police report obtained by PEOPLE.
The victim claimed Yust told her, “I’ve killed people before, even ex-girlfriends out of sheer jealousy. I will kill you,” the report states.
Yust remains behind bars at the Cass County Jail on $1 million bond, records show. He is next scheduled to appear in court on May 10.
His attorney, who has reportedly said he plans to plead not guilty, could not be reached for comment on Monday.