Jean Sinclair: Is Donald Foster’s Killer Alive or Dead?

Image Credit: Angela Snyder/Find A Grave

Investigation Discovery’s ‘Deadly Women: Jilted and Jealous’ follows the murder of Donald Foster by Jean Sinclair in January 1963 in Salt Lake City, Utah. She killed the erstwhile lover of the woman she allegedly loved and was sentenced to life in prison after being convicted of the slaying. Are you interested and want to know more about Jean? Let’s find out then.

Who is Jean Sinclair?

Isabelle Geraldine Sinclair was born on May 28, 1917, to Peter Lamond Sinclair and Ollie Jennie Hooker Sinclair. She started calling herself Geraldine after graduating high school and became Jean M. Sinclair at some point. In 1963, Jean was about 45 years of age and operated a nursing home in Salt Lake City. As per court records, she was a strong-willed individual with an apparent perversion towards the masculine side. She wore mannish-type clothes and was referred to as “King” by her acquaintances and associates owing to her strong-headedness.

Court records further state that the general belief was she had some sort of relationship with LaRae Peterson and hence was extremely jealous of Donald Leroy “Don” Foster. Though a married man, Don carried out an illicit relationship with LaRae, which her admirer and alleged lover, Jean, did not approve of. Court testimonies from various associates of her state that she harbored a violent resentment towards Don. She wanted to separate the two by hook or crook and even proposed several illegal methods to achieve her goal.

As per her associates, Vaughn Humphries and Karl Kuehne, Jean had proposed to “drug her (LaRae), strip her and put on “the Lesbian act” in a situation where Foster could see it” in an attempt to break up the affair. She had also suggested that they try to scare off Don by putting a knife to his private parts and threatening to castrate him or take the guise of a group of early Utahns, known as Danites, and castrate him. As per Karl, Jean had even talked about how Don “ought to be killed” in the fall of 1962 and offered $500 to kill Don several times.

When Karl continually refused to take her up on her offer, Jean forced him several times to drive around in search of Don so that Jean could allegedly kill him. In the last week of December 1962, she got him to buy her a 12-gauge shotgun and some shells under the pretense of shooting on a farm. Jean brought the gun to him on January 4, 1963, got him to saw off the barrel, and left him home at around 11:00 am with the weapon and ammunition. As per reports, she was wearing boots and gray men’s pants and had wrapped the shotgun in a tan trench coat.

Don and LaRae had returned from watching a movie in the early morning hours of January 5, 1963. They had pulled into the parking lot in the rear of the Don’s Susan Kay Arms apartments, between 5th and 6th North on 2nd West in Salt Lake City. After getting out of the car, he had reached out to grab his overcoat from the rear seat when he was shot at close range in the neck and face with a shotgun by Jean. She then proceeded to return to Karl’s home at around 1:00 am and stated, “Well, I killed the son-of-a bitch.”

Jean went on to intimidate Karl to get rid of the murder weapon and threatened to incriminate him in the murder as an accomplice if he did not follow her orders or open his mouth to anyone. However, detectives investigating Don’s murder were quick to catch Jean based on testimonies of different witnesses who had allegedly seen her commit the crime and flee the crime scene.

Jean Sinclair Died in 1973

Investigators proceeded to arrest and charge Jean Sinclair with first-degree murder and Karl served as the primary witness for the prosecution in her April 1963 trial in the Third District Court. She reportedly had an all-male jury, and the prosecution underlined the alleged homosexual relationship she shared with LaRae as being the primary motive behind the murder. After deliberating for 17 hours, the jury came up with a guilty verdict on May 3, 1963, and recommended leniency to the judge. Less than half an hour after the sentencing, her defense lawyer got Jean released from jail on a $100 appeal bond.

The court handed her a life sentence and she was again incarcerated at the Utah State Prison in April 1964. Jean served her sentence for about 9 years before suffering from a stroke while being held in Weber County Jail and had to be kept in a rest home in Weber County for several months. She was out on parole on May 15, 1973, on grounds of health problems. However, Jean breathed her last on July 3, 1973, at the age of 56.

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