In Plain Sight on Investigation Discovery takes a closer look at the case of Robert Spangler, who admitted to murdering his first wife and their two children, as well as his third wife, Donna Sundling Spangler.
On the morning of December 30, 1978, police officers with the Arapahoe County Police Department were dispatched to a home in Littleton, Colorado, after receiving a 911 call from an individual claiming to have found their neighbors dead inside their home.
When deputies arrived on the scene, they found the bodies of 45-year-old Nancy Spangler and her two children—17-year-old David and 15-year-old Susan. They had been shot to death with a .38 caliber handgun belonging to Robert.
A suicide note was left near Nancy’s body, and it was signed with her initials. When Robert returned to his home, investigators were still at the scene. He told them that he wasn’t there when the incident took place and said he last saw his family earlier that morning.
In 1979, an Arapahoe County medical examiner closed the case and ruled the Spangler family deaths a murder-suicide.
Robert went on to marry Sharon Cooper Spangler, who took her life in 1994. Afterwards, he married Donna, who died in 1993 while visiting the Grand Canyon. Robert told police that she accidentally fell to her death from a 160-foot cliff.
He was never charged with any of the murders, but after Donna’s death, investigators reopened the cases.
When detectives went to Robert’s home on September 14, 2000, to inform him that he was going to be indicted for the murders of Nancy, Donna, and his children, he confessed.
In a videotaped confession, Robert told investigators that he shot his first wife and their children because they were interfering with his relationship with Sharon Cooper, a woman he was having an affair with. He also confessed to killing Donna 15 years later by pushing her off a cliff.
Robert was arrested, and he later pled guilty in an Arizona courtroom. He was sentenced to life in prison without the possibility of parole.
He died in 2001 from lung and brain cancer.
In Plain Sight — Terrified To Death, airs at 9/8c on Investigation Discovery.