Woman Poisons Father With Horse Tranquilizer, Buries Body In Basement Crawl Space

Dayna Jennings lived in her father's home for several weeks after encasing his remains in concrete in a basement crawl space.

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The Case Of Dayna Jennings
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The Case Of Dayna Jennings

Federal Heights Police Detective Burke Payne opens up about the case of William Mussack, who was killed by his daughter, Dayna Jennings. Jennings poisoned Mussack and then buried his body in the crawl space of his home. She was later found guilty of murder and given a life sentence.

Shortly after the Christmas holiday on the evening of Dec. 28, 2017, Robert Mussack called 911 dispatch in Federal Heights, Colorado to request a wellness check on his brother, Bill Mussack, whom he had not heard from in more than two weeks. 

At the time of his disappearance, Bill, 69, was sharing his home with his adult daughter, Dayna Jennings, and officers were dispatched to the home to check on him. When they arrived, they were greeted by Dayna, a local massage therapist, who said her father “didn’t really live” at the house anymore and only came by every few days, according to body cam footage obtained by “Snapped,” airing Sundays at 6/5c on Oxygen

She claimed she had not seen Bill in about 10 days and that he had lost his phone, which she later found inside the house and placed by a stack of mail for him to pick up whenever he returned. 

Despite Dayna’s explanation, police soon heard from another member of the family, Bill’s son, Brian Mussack, who said he became concerned after not speaking to his father for several days. Just minutes after authorities heard from Bill, Robert called the police a second time to file a missing persons report. 

“When you start getting those multiple calls like that, this was adding up to more than just your run-of-the-mill missing persons case,” Federal Heights Police Commander Patrick Murphy told “Snapped.” 

On Dec. 29, authorities returned to the home and again spoke with Dayna, who claimed Bill had gone camping in the mountains with his friend “Martha,” but she did not know her address or last name.  

Dayna allowed the officer to look around the home, and when he walked through the front door, he was hit with an extremely foul odor, which Jennings attributed to a toilet overflow in the basement. 

She continued to tell the officer that Bill didn’t have his own room in the house anymore and that when he did sleep over, he would crash on her massage table. While searching the home, the officer found none of Bill’s personal items, and there was no evidence that he was still living there or had been at the house recently. 

“It’s his house. For him to sleep in the La-Z-Boy or on the massage table in the middle of the living room is kind of odd,” Federal Heights Police Officer Mark Burandt told producers. 

Hoping to find out more information about Bill’s whereabouts, investigators tracked down Martha’s phone number. Speaking with police, Martha said that she did own a camping property, but she had not seen or heard from Bill since early December, which she thought was out of character. 

Officers then returned to the Mussack home to speak with Dayna, who claimed although she had still not seen her father, the rent money she had left on the counter had been picked up along with Bill’s cellphone. 

Dayna told police she had no idea where Bill was and was done answering questions, later telling Bill’s friend and neighbor that he had left to spend time on a friend’s property in Arizona. Loved ones, however, said Bill knew no one in the state. 

Authorities also contacted Bill’s phone subscriber to perform an emergency ping on his device, and they discovered that the last time the device was used was on Dec. 29 near his house, not Arizona. 

“It just really hit me that he was probably dead somewhere, that something horrible had happened to him,” Brian told “Snapped.” 

Dayna Jennings William Mussack Spd 2715

Investigators soon turned to Brian, who said that during one of his last conversations with his father, Bill discussed an odd encounter with Dayna. Bill said that Dayna had picked up a burger and milkshake for him, and after taking a bite, he passed out and woke up 15 hours later.  

Bill then said, “I don’t know if Dayna drugged me or what,” according to Brian. 

Digging deeper into Dayna and Bill’s relationship, authorities learned that while the father and daughter were close, problems had recently sprung up between the two. Dayna had trouble making rent and had started taking over the house as her own, resulting in frequent arguments.  

Looking into Bill’s bank records, they found several recent cash withdrawals from his account, and the bank noted the signatures were not a match to Bill’s and that they had been filled out by Dayna.  

This discovery, combined with her odd behavior and refusal to continue cooperating with the investigation, put her at the top of the suspect list. 

Authorities then spoke with Dayna’s ex-husband, Joel Jennings, who shared his suspicion that Bill was likely dead, and that Dayna might be involved in his disappearance.  

“I think there was some sort of impropriety. I can’t tell you if Bill was murdered, or if Bill died, and was disposed of for financial gain,” Joel told investigators in footage obtained by “Snapped.” 

He added that 2017 had been a particularly difficult year for Dayna, and that her massage business had gone under, calling his ex-wife “impulsive and unpredictable.” 

With the evidence mounting against Dayna, authorities secured a search warrant for Bill’s home and arrived the afternoon of Jan. 10, 2018.  

“We have a horrendous smell in the house. This is unbearable. You could not stay in the house without some type of face mask,” Murphy told “Snapped.” 

Authorities isolated the source of stench in the basement behind a wooden board that had been placed across the entrance to a crawl space. There, they found an amateurishly laid slab of concrete, and the fire department was called in to break it apart with hammers and saws. 

Below the slab, they found a human hand sticking out of a pile of trash and debris, and Dayna was quickly taken into custody. An autopsy confirmed the remains belonged to Bill. 

While a standard toxicology report showed nothing suspicious in Bill’s system, authorities subpoenaed Dayna’s phone and laptop for more answers.  

On Dec. 9, Dayna had conducted a Google search on how long it takes bodies to decompose, and during a previous search, she looked up acepromazine, a horse tranquilizer, which she ordered off eBay in late November.  

Authorities then had Bill’s remains tested for acepromazine, and the results came back positive. He had been slipped a dose that was enough to tranquilize several horses, and Dayna was charged with first-degree murder and tampering with a deceased human body, according to “Snapped.” 

At trial, the defense argued that Dayna had bought the drug to help with Bill’s health and sleeping issues. They claimed she had no intention of killing her father and that it was an accidental overdose. Once Bill died, they contended Dayna did not know what to do and buried him in basement.  

Prosecutors, on the other hand, argued Dayna had murdered Bill in order to take over his home and finances. 

On July 15, 2019, the jury returned with a verdict — Dayna was guilty of first-degree murder and tampering with a deceased human body. She was sentenced to life in prison without possibility of parole.  

To learn more about the disturbing case, watch “Snapped” now on Oxygen.com

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