Updated: June 4, 2014 at 6:41 pm
Brendan Lee Johnson, 19, and Cassandra Ann Rieb, 18, appeared in court in Sterling, a small city on Colorado's rural northeastern plains, a day after they were arrested in the deaths of Charles and Shirley Severance, both 70. The teens told authorities they had planned since early May to smother Johnson's grandparents with pillows as they slept, but their efforts were complicated when the couple put up a struggle.
Police said the teens told them the killings happened May 20. When authorities discovered Charles Severance's body nine days later after receiving a medical call at his home, his wife was missing. Investigators on Monday discovered some of her remains near Sterling and others about 30 miles away in Lorenzo, Nebraska.
"Together we went and we did it together," Rieb told investigators, according to the court documents. "We had agreed to do it together, obviously. ... Like one get one and one get the other."
Johnson's attorney, Rachel Lanzen, did not return calls seeking comment, and it was unclear who would be representing Rieb. Jill Johnson, Brendan's mother and Shirley Severance's daughter, declined to comment to The Associated Press on Wednesday and asked for privacy. Calls to possible listed phone numbers for Rieb went unanswered or messages were left that weren't immediately returned.
Rieb said the plan was to hasten Johnson's inheritance, which included the grandparents' low-slung home, valued at just $47,000.
The teens crept into the home early in the morning, but Charles Severance was awake and fought Johnson, according to the documents. Johnson told authorities he tried to choke his grandfather, who he believed then died of a heart attack.
Shirley Severance asked, "Why are you doing this to me?" and offered the combination to her safe as Johnson and Rieb strangled her, according to the documents. As she attempted to open the safe, Johnson grabbed a kitchen knife and stabbed his grandmother, authorities said.
In the days that followed, the couple told police that they cleaned the home, gathered up evidence and drove to Nebraska, the documents say. They said they had planned to cut up and burn both bodies, but left Charles Severance's behind because it was too heavy, the records say.
They burned Shirley Severance's body in a fire pit near Sterling but later dug it up and took some remains to Nebraska, police said.
A judge on Wednesday advised the teens of possible charges, which could include first-degree murder, aggravated robbery, forgery and theft. Both were held without bond.
Shirley Severance's half-sister, Norma Curl, said Johnson recently graduated from high school and had been living with his grandparents, but she didn't know why. Last week, Johnson's mother sent Curl a Facebook message that read, "There's no easy way to say this. The police found my dad dead and Mom is missing," Curl told The Associated Press.
A few days later, an officer called Curl, asking questions about Johnson. His Tuesday arrest stunned the family, Curl said, but she was not surprised to hear that her sister, outspoken and opinionated, put up a fight.