Man sitting along highway confesses to woman's 2016 murder

A routine welfare check in Oklahoma last week led to an unexpected development in a murder cold case. While sitting along the side of an interstate highway outside of Oklahoma City, authorities say that Joseph Beck voluntarily confessed to killing 19-year-old Jennifer Kyli Molloy in 2016.

Beck offered the confession to a state trooper, who performed the welfare check on Thursday after a passerby reported seeing a man by himself near an exit off I-40, according to Oklahoma Highway Patrol. The trooper took Beck to the Edmond Police Department, which had initially investigated Molloy's killing. Detectives eventually arrested the 28-year-old as a suspect in her death and charged him with first-degree murder. Records show that Beck was booked into the Oklahoma County Detention Center on Friday, and was still being held there as of Monday morning.

Oklahoma Highway Patrol said they "hope this ultimately ends in answers for an Oklahoma family."

Molloy was found dead in her apartment in Edmond, about 15 miles north of Oklahoma City, on Oct. 5, 2016, the Edmond Police Department said in a statement. Police characterized her death as "suspicious." They said that the investigation into what happened to her turned up several leads over the years, but no arrests had previously been made.

Beck confessed to strangling Molloy to death, CBS affiliate KWTV reported. Edmond police told the station that Beck became their primary suspect in the former cold case once he shared specific details about the murder. During an interview with investigators, he said that he and Molloy worked together and confessed to being attracted to her, according to KWTV. Leading up to the killing, Beck recalled going to Molloy's apartment, intending to assault her, and feeling angry when she asked him to leave. Then, he said, he killed her.

Johnny Molloy, the victim's father, told KWTV that he was shocked and angry when he learned about Beck's confession, but the arrest also brought some closure.

"I've been waiting on this for a long, long time and I never really thought it would happen," he said. Although the exact nature of Beck and Kyli Molloy's relationship outside of work is unclear, her family told KWTV that they had known the suspect for a while.

"Growing up with Joseph, he was the nicest guy, he was the sweetest guy," Christa Stanfiel, the victim's sister, told the station. "You would never think anything ill-mannered from him and to know this happened and that he did this over something so stupid."

Stanfiel said that Beck contacted her months after her sister's death and wanted to meet, according to KWTV. He continued to reach out to her until as recently as April of this year, but she never responded to his messages. CBS News contacted the Edmond Police Department for more information but did not receive an immediate reply.