The question was never if one of the two Rouse brothers had murdered their parents, but rather, which one had carried out the double homicide.
Was it Kurt, the 20-year-old, long-haired rock musician, or Billy, the troubled 15-year old?
It took investigators more than a decade to find out the truth, and the investigation ended in a confession that no one saw coming.
Bruce Rouse was born in 1936, and his family ran a successful gas station and car wash in Mundelein, Illinois, north of Chicago. Brought up with a strong work ethic, Bruce worked various jobs before opening his own fleet of gas stations and service centers.
He later married his high school sweetheart, Darlene Stenlund, and the following year, their first son, Kurt, was born. Their daughter, Robin, was born three years later, and William, or Billy as he was known, was the baby of the family, born in 1964.
Bruce used his initial success to invest in other businesses, including real estate and cable television, and the family eventually settled into a 13-room, six-acre mansion in the Chicago suburb of Libertyville.
After graduating from high school, Kurt moved into a cottage on the Rouse property, which allowed him to party and play his music as loud as he wanted without the peering eyes of his parents. Kurt reportedly butted heads with his parents, who changed the locks on their doors in order to keep him out, according to a 1995 report by the Chicago Tribune.
Billy, meanwhile, landed in trouble as early as 6th grade and was accused of vandalizing several local schools. Feeling ignored by his workaholic father, he later told police, "I wanted his attention, so I set his bed on fire," reported Chicago’s Daily Herald newspaper.
"He was bad news from nursery school," an anonymous neighbor told the Chicago Tribune in 1995. "A gross delinquent, always in trouble of one kind or another. Even as a little kid."
Billy’s older brother believed his problems were rooted in undiagnosed learning problems.
“I think Billy had some learning disabilities. Maybe some dyslexia, and also he was one of the kids who smoked cigarettes and who got in trouble,” Kurt told “Snapped,” airing Sundays at 6/5c on Oxygen.
On June 6, 1980, Bruce failed to show up for work, which came as a shock to his employees as he always arrived at 5:30 every morning.
When an employee called the house, Billy answered the phone, and he went to go check on his parents. The man then heard “pandemonium, he hears screaming,” Chief Deputy State’s Attorney Jeffrey Pavletic told “Snapped.”
At the Rouse house, first responders found a distraught Robin, who “pointed us to the master bedroom and said, ‘Mom and Dad have been shot,’” Libertyville Fire Department Captain Robert Zamor told “Snapped.”
There, investigators found a gruesome and bloody crime scene. Darlene had been shot in the face as she was lying in bed. Beside her was Bruce, whose lower jaw had been shot off. He also showed signs of blunt force trauma to the head and had sustained multiple stab wounds. Both were pronounced dead at the scene.
Kurt said he had been asleep in the cottage when Billy came down to tell him what had happened.
“I think he said, ‘Mom and Dad are dead.’ I looked behind him, and there was a police officer with a gun aimed at my head,” Kurt told “Snapped.” “It was like waking up into a nightmare.”
The Rouse children told investigators they hadn’t heard or seen anything suspicious on the night of the murder as there had been a violent thunderstorm, which could have covered up the sound of gunshots. The coroner determined the Rouses’ time of death was between 2 and 3 a.m.
Kurt told police he was out with his girlfriend that night, and Robin said she had been at a school dance and hadn’t returned until after midnight. Billy also claimed he was out with friends, arriving home late at night.
Investigators initially theorized the murder could have been a robbery gone wrong because the Rouses’ bedroom appeared to have been ransacked, and their children said the family seldom locked their doors.
“I don’t know that anybody in the family actually carried a key,” Kurt told producers. “It was just that kind of feeling in Libertyville, that you could just leave your doors open, and no one was going to wander in your house.”
While investigators worked the crime scene, members of the extended Rouse family arrived at the house. When the Rouse children were asked to come down to the police station for further interviews, their relatives intervened and obtained legal counsel for them.
About six weeks later, Billy asked to speak with investigators and see photos of the crime scene. After reviewing them, he said his mother’s purse and jewelry box were missing from the bedroom, as were his father’s shotguns and rifles.
Four months after the murders, surveyor Jeffrey Carlson was working in the nearby Des Plaines River and nearly tripped over a garbage bag. Inside, there was a jewelry box and a woman’s purse.
He pulled the driver’s license out of the wallet, and “saw the name Darlene Rouse," Carlson later testified, according to the Chicago Tribune.
After alerting authorities, investigators dredged the riverbed and found four shotguns and a rifle, which belonged to Bruce. With robbery no longer a viable motive, rumors swirled that the Rouses were somehow involved with organized crime. Investigators, however, concluded that the speculations were untrue.
Each of the Rouse children were later awarded $300,000 on a life insurance policy in their parents’ name, according to "Snapped." Kurt moved to California and later Iowa, trying to put his traumatic past behind him.
While each of them attempted to move on with their lives, tragedy was not through with them just yet.
In 1983, Robin told authorities that she suspected one of her brothers was responsible for her parents’ murder, but the day before she was set to talk to police, she got into an accident. She lost control of her car in Racine, Wisconsin, where she was attending college, and died in a fatal car crash.
After receiving his insurance payout and finishing high school, Billy moved to Key West, Florida, where he stabbed a man over a game of chess in 1984 and spent 60 days in jail, according to South Florida’s Sun-Sentinel newspaper.
Following his stint behind bards, Billy tried to straighten out, and he got married, had a kid, and bought a house. The couple fought frequently, however, and Billy drowned his troubles in drink. He blew through his money in short order and got divorced, and by the early 1990s, he was living alone on a derelict houseboat and racking numerous arrests for petty offenses.
In September 1995, Billy and some of his drinking buddies robbed a bank, and they were busted after making off with around $5,000.
After hearing that Billy had been arrested, a team of detectives from Illinois traveled to Florida to see if there was anything Billy wanted to get off his chest.
He ended up telling them everything.
Billy said that on the night of his parents’ murder, he had gotten into a fight with his mother after coming home drunk.
“She says, ‘Yeah, don’t worry about it. You’re going to be shipped out to military school. I’m just over it. You f--king moron,’” Billy told detectives in a recording obtained by “Snapped.”
After drinking some whisky and eating some psychedelic mushrooms, he said he “simply decided I was going to get rid of my mom.” Billy went into the closet where his father kept his guns, pulled out a 16-gauge semi-automatic shotgun and loaded it.
He then went into his parents’ bedroom, where they were both sleeping, and “took the 16-gauge, put it up to her head, and the trigger went off.” The blast woke up his father, who then “sat up real quick, looked at me, and the trigger went off again.”
While Billy had blown off his father’s lower jaw, the wound didn’t kill him, and he began beating his father on the head with the butt of the rifle.
“I didn’t want him in f--king misery, so I grabbed the f--king knife and I stabbed him until he quit moving,” Billy told investigators.
When asked if he was sorry his parents were dead, Billy responded, “Yes and no.” He said that while he was glad he didn’t have to deal with them anymore, he expressed regret because “it really f--ked up my sister.”
In 1996, Billy was found guilty on two counts of murder for killing his parents, reported the Associated Press.
Two months later, Billy was sentenced to two consecutive 40-year prison terms. Presiding Judge Victoria A. Rossetti said she was “disgusted” she could not give him a life sentence, according to the Chicago Tribune.
Billy isn’t eligible for parole until 2035, when he will be 71 years old.
To learn more about the case, watch "Snapped" on Oxygen.
Crime Time is your destination for true crime stories from around the world, breaking crime news, and information about Oxygen's original true crime shows and documentaries. Sign up for our Crime Time Newsletter and subscribe to our true crime podcast Martinis & Murder for all the best true crime content.