Teenage couple 'murder grandparents before throwing house party with bodies still present'

Cassandra Bjorge and boyfriend Johnny Rider charged with murder and aggravated assault

Johnny Rider and Cassandra Bjorge are charged with murder and aggravated assault for the death of 63-year-old Wendy and Randall Bjorge (Gwinnett Police Department)

A teenager and her boyfriend allegedly murdered her grandparents and threw a drug-fuelled party days after the killing, while the corpses were decomposing in another room, police have said.

Cassandra Bjorge, 17, and her 19-year-old boyfriend Johnny Rider reportedly stayed in the Lawrenceville home in Georgia, US, for days after killing 63-year-old Wendy and Randall Bjorge.

Local TV channel WSB-TV reported the couple corked two doors in the house and the front door of the home to keep the smell out.

Later, they invited friends around and smoked cannabis, the local news channel reports.

Gwinnett County Police said the victims had suffered “blunt force trauma and sharp force injuries” and the youngsters reportedly beat their victims with a hammer and a baseball bat before slitting their throat.

Detective Dave Brucz told the court: "Johnny began to attack the grandmother. Bjorge then said she had a surge of energy. She then dragged her grandmother into her grandfather's bedroom. She was duck taped."

Bjorge reportedly confessed to the crime.

Police said they believed the elderly couple died about a week before they forced entry into their home and discovered the bodies on 8 April. According to police reports, they were responding to an assault call, when the teenagers attacked Rider’s sister and her boyfriend.

The pair have been charged with murder and aggravated assault.

In a statement, Gwinnett County Police said: “This is a very unique and disturbing case on so many levels and detectives are still exploring motive. We may never find a scenario that makes sense to a reasonable person.”

Authorities later said Bjorge and Rider decided to murder the couple because they “basically had enough of them”, the Daily News reports.

They also claimed the youngsters had planned to murder other family members, including Bjorge’s mother Amanda Sterling.

Speaking to Channel 2 Action News, Ms Sterling said: “In not a million years would I ever think something like this would ever happen. I need hope and strength for the days to come because it is going to be a long road.”