How did investigators find Katherine Mordick's killer and where is he now?

Katherine Mordick's 1983 murder case remained unsolved for nearly three decades until forensics could finally connect the DNA found at the crime scene to the alleged murderer, her husband William Gregory Mordick.

Investigators initially suspected Gregory of murder based on circumstantial evidence, such as his diary entries detailing his turbulent relationship with Katherine. Authorities finally linked him to the crime years later, thanks to DNA testing that was not available at the time.

On February 6, 2008, Gregory was taken into custody at his Spokane, Washington, residence. He was found guilty of the first-degree murder of Katherine Mordick in 2011 and sentenced to 25 years to life in prison. Earlier, the victim's family had also expressed their deep suspicions about his involvement in the murder.

Now that Dateline: Secrets Uncovered is set to re-examine the case and give all the gory details about what happened on January 22, 1983, at the former couple's Ridgecrest home, here's everything you need to know about the case's findings.

Trigger warning: This article contains information about graphic violence.

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Katherine Mordick's estranged husband allegedly murdered her to save up on child support

Gregory Mordick was a photographer who was struggling to make ends meet at the time of his wife's murder. While he worked as a photographer, his wife, Katherine Mordick, worked as a "food stylist," styling meals for print and television advertisements. Katherine allegedly had an affair with coworker Henry Bjoin.

The main motivator, according to the prosecution, was Gregory's fear of losing custody of his daughters and having them return home with his ex-wife and Bjoin, who were planning to move in together. Mordick allegedly wanted his wife dead in order to avoid paying her $124,000 in child support over a 16-year period.

Katherine Mordick's portrait captured before her 1983 murder (Image via NBC)

According to the prosecution, he had the perfect opportunity to murder his wife on January 22, while picking up his daughters for a weekend visit to take them to a birthday party in Huntington Beach. The divorce hearing was scheduled for a few days later. Katherine Mordick, according to reports, planned to pack her belongings for her move that weekend.

After failing to contact Katherine over the weekend, Bjoin went to her Ridgecrest home the following Monday with her brother, Joseph O'Connell, and discovered her body. Her blood-stained body was discovered with her throat slashed open on January 23, 1983.

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Katherine Mordick's killer husband found guilty based on decades-old DNA evidence

Gregory Mordick was found guilty during a January 2011 trial (Image via NBC)

After nearly two days of deliberation, the jury decided to convict Mordick based on DNA evidence found throughout the house. Before being apprehended in 2008, Gregory reportedly raised his motherless daughters in Washington State. The final decision came two and a half years after his arrest.

Furthermore, excerpts from Mordick's journal on his wife's affair with Bjoin revealed that he grew increasingly enraged over the affair and even assaulted her on multiple occasions in front of their daughters and the victim's sister.

The jury did not convict Gregory of murder for monetary gain, which would have resulted in a life sentence with no chance of parole. Gregory was found guilty of first-degree murder and sentenced to life in a California state prison for 25 years.

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Dateline: Secrets Uncovered airs on Wednesday, August 24, 2022, at 8 pm ET on Oxygen.