5 things to know about Robin Hoynes murder case

The upcoming episode of NBC's Dateline: Secrets Uncovered delves into the grisly murder of 21-year-old Robin Hoynes in 1984, a case that remained unsolved for over two decades.

Revisiting the crime on August 3, 2022 is the upcoming episode of Season 10, titled The Night Before Halloween. New episodes are released weekly at 8 pm. The official synopsis for the episode reads:

"It takes a special eye to spot the thing that's out of place at a crime scene; in this case, that thing looks so insignificant, no one even knows what it is or what it means; it takes a team of determined investigators almost two decades to find out."

Here's all you need to know about the murder case ahead of the episode release.

Exploring the 1984 murder of Robin Hoynes ahead of the Dateline: Secrets Uncovered episode

1) Who was Robin Hoynes?

Robin Lucille Hoynes was a 21-year-old woman hailing from Whittier, California. On the eve of Halloween in 1984, she was murdered in cold blood while working her shift as the assistant manager at Kentucky Fried Chicken in Torrance.

Cheryl Fuller, a former assistant manager at Kentucky Fried Chicken, who had traded shifts with Hoynes that night, discovered her body the next morning. She found the victim's yellow Datsun parked outside and the employee door unlocked.

She found Hoynes' body on the floor and assumed that she was sleeping until she saw blood on her face and neck. She also noticed paperwork and debris scattered on the floor, including photos of Hoynes' nieces and nephews, and a piece of foam.

2) How was Robin Hoynes murdered?

Authorities reported that she had become a victim in an attempted robbery. She was stabbed in the back twice before her throat was slashed.

According to the medical examiner, Hoynes had two stab wounds in the back, one fatal and one potentially fatal. Her throat was slit at or near the time of death.

3) Who murdered Robin Hoynes?

William Charles Marshall was the prime suspect in the Robin Hoynes murder case. He was an employee at Kentucky Fried Chicken, but was fired from his job days before the killing due to suspicions of him stealing.

12 days after the murder, police arrested Marshall, but prosecutors did not file any charges at the time and the case remained cold until 2005.

After taking a fresh look at the cold case, Torrance Police Department officials rearrested Marshall in 2005. Marshall, 46, was the captain of the State Department of Forestry and Fire Protection in the Coachella Valley community of Thousand Palms at the time of his arrest.

In 2007, a jury found him guilty of the 1984 murder of Robin Hoynes. He was sentenced to life in prison without the possibility of parole.

4) How did a piece of foam become crucial in solving Robin Hoynes' case?

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On October 31, 1984, the crime scene of Robin Hoynes' murder had something odd and insignificant lying in its midst. It was a piece of foam that had perplexed the investigators at the time. Eventually, when the case was reopened in 2005, detectives tied it to a pair of Marshall's boots that had been seized at the time of his arrest.

5) Who is Yvonne Williams and how did she help the case?

Yvonne Williams was Marshall's girlfriend in 1984, when he murdered Robin Hoynes in cold blood. He confessed his crime to her and the two evaded justice by keeping it a secret and lying to the authorities.

However, when the case was reopened, Williams came clean to the detectives and took the stand in court to share the details of the crime. The couple were drug users during that time and stayed together for three more years after the murder.

Tune in to the true crime series to learn more about the robbery and murder that shook the city of Torrance decades ago.