A phone call made to police three days before the body of JonBenet Ramsey was found in the basement of her family home may shed new light on the historic murder case.

Lisa Wilson and Nick Van der Leek, authors of the Craven Silence trilogy, claim a silent phone call made to Boulder, Colorado police on December 23, 1996, from John and Patsy Ramsey’s home may highlight the duplicitous nature of the family’s close inner circle.

“We believe something happened at the party, something serious,” the authors told News Corp .

“Secrets kept on December 23 were repeated under far more serious circumstances three days later. This time the Ramseys knew they could rely on their friends to keep their secrets. Their friends assumed the Ramseys were innocent, and if they felt otherwise later, they were ostracised, sued or accused.”

New light still being shined on the 20-year-old mystery surrounded the death of JonBenet Ramsey.

On the eve of December 23, police responded to the silent 911 call and visited the Ramsey’s home.

They were met at the door by Susan Stine, a family friend attending a lavish Christmas party. Stine told authorities the call was made by someone trying to purchase medicine and they had dialled the emergency number by mistake, but would not let police into the home to investigate.

Three days later, authorities returned to the Ramsey’s estate where they found six-year-old JonBenet dead in the basement with a blow to her head, a garrotte around her neck and unidentified DNA in her underwear and on her pyjamas.

John and Patsy Ramsey

A three-page ransom note was also found in the home, demanding $118,000 USD – almost the exact amount of father John's latest bonus payout.

In September, The Case of JonBenet Ramsey documentary on Channel Nine claimed JonBenet’s older brother Burke likely killed his sister with a blow to head and that his parents helped cover up the crime.

The claim was made by former FBI special agent Jim Clemente and an assembled panel of forensics and crime experts.

The three page ransom note found in the Ramsey home

The unanimous theory is that Burke, aged nine at the time, hit his sister in the head with a heavy torch, likely out of anger, but not intending to kill her.

After being put to bed, JonBenet wandered downstairs and interrupted Burke who was eating his sister's favourite dessert of pineapple and milk at the kitchen table.

The docu-series claimed some kind of argument transpired, possibly incited by JonBenet stealing a piece of pineapple from Burke's bowl.

Clemente and the group believed this caused her brother to lash out.

On discovering the accident, the quoted experts said all evidence pointed to an elaborate cover up and staging of a crime scene by parents John and Patsy Ramsey.

Both parents always strongly denied they were involved in the murder that has baffled the world for 20 years.

Burke and JonBenet Ramsey.

Burke refuted the documentary and has filed a $195 million defamation lawsuit against panel member, forensic pathologist Dr Werner Spitz over his character assessment.

However, The Craven Silence authors believe Burke’s alleged murder of his sister was not an accident and was incited by deep-seated jealousy of his sister’s beauty and outgoing personality.

The pair claim JonBenet receiving a bicycle in 1996 for Christmas while he didn’t may have set him over the edge.

The Ramsey's have refuted their involvement in their daughter's murder.