Murder of Bill Mussack by daughter Dayna Jennings investigated on Diabolical

Mugshot of Dayna Jennings
Dayna Jennings was sentenced to life in prison for killing her father, Bill Mussack. Pic credit: Adams County Sheriff’s Office

Diabolical is in Federal Heights in Colorado to investigate the murder of Bill Mussack, who was poisoned by his own daughter, Dayna Jennings, in 2017.

Relatives became suspicious after failing to make contact with 69-year-old Bill in December of 2017, so they asked the local police department to perform a welfare check on the veteran.

Officers attempted to perform multiple welfare checks on Bill at the home he shared with his daughter, Jennings, in the Denver suburb, but they were always prevented from searching the house.

On one occasion, the police detected a bad smell that indicated something was rotten, but Jennings told the police that the toilet was blocked. She also told them that her father had gone to the mountains to be with his girlfriend.

Eventually, on January 10, 2018, the police returned to the house with a search warrant. They discovered Bill’s remains encased in concrete and debris in a crawl space of his home.

An autopsy revealed that Bill had ingested a poison known as acepromazine, an animal tranquilizer. If administered to a human, it slows down the respiratory system until the person stops breathing and the heart stops.

Bill Mussack suspected Dayna Jennings was drugging him

The police believe that Mussack had begun to suspect his daughter was trying to kill him. He had texted his son on December 7, 2017, to say he’d slept for 15 hours after Jennings had fed him a meal.

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In the text, he told his son: “I keep telling her she must have drugged me.” The investigators also learned that he had been researching the effects of acepromazine on the human body before he died.

The detectives realized that shortly after her father had passed away, Jennings had purchased a dumpster and some concrete from a Home Depot. She’d also used Bill’s credit card to pay for it.

At one point after the murder, Jennings even texted a friend to say, “life is so different now I feel so much better.”

In July 2019, Jennings was found guilty and convicted of first-degree murder and tampering with a corpse. The following month she was sentenced to life in prison without the possibility of parole.

More from Diabolical

Follow the links to read about more diabolical murders profiled on ID.

Vanessa Cameron decided to have her ex-boyfriend Samuel Johnson in a barbaric scheme that would see her collect thousands of dollars in life insurance. Cameron recruited her sister, brother-in-law, and his cousin to help her with the killing.

Kevin Boyd Sr. was stabbed over 20 times and beaten to death with a baseball bat. His killers were his ex-wife Lynn Boyd and his teenage son Kevin Boyd Jr. They had hoped to collect on a $500,000 life insurance policy.

Diabolical airs at 8/7c on Investigation Discovery.

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