A Pennsylvania cold case is back in the news as the family of Matthew McDonald, a Pennsylvania man who vanished on March 9, 2023, demands answers. The calls come amid chilling allegations involving his ex-girlfriend and his girlfriend at the time he disappeared.
New scrutiny has emerged following viral social media content in which McDonald’s ex, Sierra, appears to sing lyrics referencing murder — “I just killed my ex” — using video clips posted on McDonald’s own accounts.
Meanwhile, inconsistencies in the narrative offered by his girlfriend at the time, Kylie Humphreys, have only deepened suspicion and frustration about the lack of progress in the case among McDonald’s loved ones.
Neither Humphrey or his ex, only known as Sierra, have been accused of any crime and neither one has been named a suspect or a person of interest in the case.
Matthew’s disappearance: the official story
@mattthibodeau #MatthewMcDonald has not been seen since March 9th, 2023. His GF & ex GF not only didn’t report him missing right away, but they were using his phone after he disappeared & pretending to be him when family would text him! Matthew’s family feels LE isn’t doing enough, so let’s put some pressure on them! #foryou #fyp #truecrime #breakingnews @Sam
♬ original sound – Matt Thibodeau
According to Humphreys, the last person to claim she saw McDonald, she dropped him off for work on the morning he disappeared, but received a call about an hour later asking her to pick him up. She says McDonald told her he was struggling and could not continue the shift. Humphreys says she rushed to get him, and even got a speeding ticket on the way.
After picking him up, Humphreys claims McDonald realized he had mistakenly grabbed his boss’ phone instead of his own. She says she left him in a cemetery so she could return to the work site and exchange the phones, and when she came back, he was gone.
But McDonald’s family and coworkers challenge that timeline. They say McDonald placed a call to his boss after Humphreys allegedly switched phones, indicating he was still active and reachable. That suggests he was not left alone in the cemetery, or perhaps was never there at all.
On the same day McDonald disappeared, police responded after Humphreys was seen on surveillance footage breaking into a church located within the cemetery grounds. However, there is no footage showing McDonald inside that church with her.
McDonald’s DNA in Humphrey’s trunk
Amid the investigation, a search warrant was executed on Humphreys’s vehicle and residence. Authorities reportedly found McDonald’s DNA in the trunk of her vehicle, though officials later said that the DNA was insufficient to indicate the presence of a body. Notably, some coworkers assert that McDonald was seen exiting Humphreys’s trunk when he arrived at his workplace that morning, a claim that raises more questions than providing answers.
Meanwhile, McDonald’s personal effects, like his wallet, ID, Social Security card, and money, remained at Humphreys’s residence, suggesting he did not plan to go anywhere.
Social media shocks: ex’s song and messaging from McDonald’s account
Where did you go Matthew? We need to know.
— Manifested Search Team (@MissingPeopleIA) August 19, 2024
MISSING Matthew McDonald
Location: California, Pennsylvania
Last Seen: March 9, 2023
McDonald was working at a job site in California, PA. McDonald was picked up by his girlfriend and driven to the area of Howe Cemetery in Long Branch… pic.twitter.com/12pTBukqIQ
What’s perhaps most eerie, though, is the alleged social media activity following McDonald’s disappearance, according to reputable true crime TikToker Matt Thibodeau and other true crime content creators. According to Thibodeau, Humphreys, and Sierra used McDonald’s phone to post on his Snapchat account. In one video, Sierra sings lyrics to the effect of, “I just killed my ex.” In another, she references, “He tried to propose to her,” meaning Humphrey’s, “with my old engagement ring.”
Humphreys and Sierra also allegedly impersonated McDonald in communications with his family in the days after his disappearance, maintaining the façade that he was safe. Only later did they respond that they had not seen him and had no idea of his whereabouts.
Friends of McDonald have shared that he had repeatedly expressed fear of Humphreys, claiming she was abusive — physically and verbally — and that he believed she might kill him. One friend said McDonald asked to stay with him to escape the relationship.
Also, a friend named “David” alleged he later began dating Humphreys (after McDonald went missing) to get information. David claimed he overheard Humphreys on a call saying she had “delivered him,” though law enforcement dismissed that tip as hearsay.
According to local law enforcement, McDonald may be deceased somewhere in rugged terrain near the cemetery. The family insists no thorough searches have been conducted there. To date, there are no new confirmed developments in the case. The family continues to urge anyone with information — no matter how small — to come forward.
