Details of Disappearance Leslee was last seen in Wolf Creek, Montana on June 10, 1975. Her husband, Dennis Raymond Larson, said they were picking mushrooms by Little Prickly Pear Creek, about a mile from Wolf Creek. Little Prickly Pear Creek feeds into the Missouri River and it was swollen with spring runoff at the time. The water level was ten feet higher than normal.
According to Dennis, the riverbank gave way under Leslee's feet. She fell into the water, went under a fallen log and disappeared. He said he jumped into the water to try and rescue her, but was unable to find her and was nearly pulled under the water himself.
When Dennis reported what had happened to Leslie, the police noted his clothing wasn't wet, which was inconsistent with his story. Leslee's body was never found, but she was presumed an accidental drowning victim. Her family was suspicious of Dennis's account for years. A photo of him is posted with this case summary.
Leslee was Dennis's first wife. He married a second time in 1982, six months before Leslee was declared legally dead. This marriage ended in divorce. Dennis's second wife had legally adopted his and Leslee's daughter, and the child remained with her after the divorce.
In October 1987, Dennis killed his third wife, Kathy Frost Larson, in Maine. They had been married less than a month and were visiting Acadia National Park when he pushed her off an 80-foot cliff. He said at the time that she accidentally fell.
Dennis was the only witness to Kathy's death and gave contradictory accounts as to what happened, making the authorities suspicious. He said he and Kathy were taking photographs of sea otters, but otters didn't live in that area of the park. Kathy's friends also said she was terrified of heights and wouldn't have gone so close to the edge of the cliff like her husband said.
Dennis moved back to Montana shortly after Kathy's death, and in February 1988, a Maine State Police detective went there to interview him about her case. It was then that he admitted he had pushed Kathy off the cliff. He was arrested, extradited back to Maine, convicted of murder and sentenced to fifty years in prison.
The authorities believe the motive was so Dennis could collect on Kathy's life insurance. He had a history of insurance fraud. He had bought a $200,000 policy for Kathy from Allstate, with double indemnity in case of accidental death. Authorities reopened the investigation into Leslee's presumed death after Dennis's arrest. He had taken out a $20,000 policy on her life, also from Allstate.
A former Montana Department of Justice investigator interviewed Dennis in prison in 2000. Dennis confessed to Leslee's murder, saying he'd pushed her into the creek and watched her drown. He said the murder was planned and he'd gone to the river with her knowing he would kill her.
Dennis was charged with Leslee's murder in October 2000. He was still in prison in Maine at the time, and said he was prepared to plead guilty in exchange for a ten-year sentence. But in 2001, before the case could proceed, Dennis committed suicide in prison.
Leslee was born in Great Falls, Montana and graduated from C.M. Russell High School in 1972. She completed a dental assistant training course and briefly worked for a dental office before her marriage. Her body has never been found.
- Lewis and Clark County Coroner's Office
Updated 2 times since October 12, 2004. Last updated September 21, 2018; picture and date of birth added.