A 70-year-old man is found dead in his house, the remains of his wife, 70, found in two separate locations

Credit: Sterling Police Department

Brendan Lee Johnson, 19 years old and living with his grandparents in Sterling, Colorado, called authorities May 29 to report a medical emergency: His grandfather was found dead in the house and his grandmother had disappeared.

Suspicious of Johnson from the start, police considered him a person of interest but did not immediately arrest him. An autopsy on Charles Severance, 70, was inconclusive – there were no signs of trauma and a toxicology report was pending.

Then on Tuesday, police announced that the remains of Shirley Severance, also 70, had been found overnight, chillingly in two different places, in different states – at the Prewitt Reservoir southwest of Sterling and at a location in Lorenzo, Nebraska, just across the border.

Johnson and his girlfriend, Cassandra Ann Rieb, an 18-year-old high school student, were arrested on charges of first-degree murder, aggravated robbery, forgery and theft, in a case that has stunned residents of this community 130 miles northeast of Denver.

“They seemed like a very happy, you know, older couple, that’s just living out their lives,” the Severances’ neighbor, Janet Lillie, tells 7News in Denver, “and to hear about that is so horrible.”

District Attorney Brittny Lewton told reporters Tuesday that a motive for the killings remained under investigation. She said that investigators “have been working pretty much nonstop the last several days putting together pieces and talking to people and sorting through the normal steps of an investigation,” but declined to say what evidence had been collected.

Even so, police chief Tyson Kerr said authorities were certain the murders had been solved. “At this time the investigation indicates that there are no other individuals involved in the crime,” he says, “and there continues to be no public safety threat.”