This week on Oxygen, Dateline: Secrets Uncovered examines the murder of Susan “Susie” Casey in Glendive, Montana, by her jealous ex-husband, Walter Martin “Marty” Larson Jr.
On April 12, 2008, Susie’s family reported the 34-year-old mother of four missing from her home. Her children told the police that she had been out late drinking with her boyfriend Brad Holzer the night before and appeared to have not returned home.
Susie was found approximately a month later in the Yellowstone River near the town of Fallon, about 30 miles upstream from Glendive by a Fish, Wildlife, and Parks employee.
The Dawson County Coroner concluded that she had been strangled before her remains were dumped in the river. There were three possible suspects, all of whom had had contact with the victim the day she died. There was her husband, Ted Casey, who she was going through a divorce with, and there was her boyfriend, Holzer, and her first husband, Larson.
Susie had married Larson in 1993, and the pair had two children before divorcing in 1998. Susie got married again later that year to Casey and had two more children. However, by the end of 2007, that relationship had also begun to break down.
Susie and her four children moved out of the family home to an apartment in Glendive, and she began a romantic relationship with Holzer.
Larson and Casey had recently started seeing each other again after being apart for nine years, despite a restraining order against him.
Watch the Latest on our YouTube ChannelLarson wanted to get back together with Casey
The police believe that Larson had been hopeful that the pair would remarry but became enraged when he discovered Susie had begun a relationship with another man, Brad Holzer.
Larson tried to break up the relationship by making anonymous phone calls and sending harassing emails. When that failed to end the budding romance, he decided to drive to her apartment and wait for Casey to come home after a night out with Holzer.
The police believe that Larson was waiting outside Susie’s home when Holzer picked her up at about 11 pm, and they suspect he was still there when he dropped her off again approximately five hours later. It was at this point that Larson murdered Susie.
Larson admitted to being in the area that night but claimed he was worried about Susie, so had driven to her place to make sure she was ok but left when he concluded she was safely inside.
It took detectives four years to build a case against Larson, but they finally arrested him in Phoenix, Arizona, in 2012, where he had moved to a few months after the murder. He was sentenced to 100 years in prison.
More from Dateline: Secrets Uncovered
Follow the links to read about more crimes profiled on Dateline: Secrets Uncovered.
Moviemaker Mark Twitchell decided that the best way to make a film about a serial killer was to become one. He lured Johnny Altinger to his home by pretending to be a woman searching for a date online. He stabbed Altinger with a knife and buried his body in a sewer.
Stephen McDaniels fantasized about committing the perfect murder, so he killed aspiring law student 27-year-old Lauren Giddings, at their apartment complex in Macon, Georgia. However, he made so many mistakes that the cops quickly tracked him down.
Dateline: Secrets Uncovered airs at 6/5c on Investigation Discovery.