Sixteen years after JonBenet Ramsay's body was found bound and gagged in the basement of the family home in America, a detective who worked on the case says vital clues may have been missed in the hunt for her killer.

The murder of six-year-old JonBenet has captivated America.

Police scrutiny fell on the family almost as soon as her body was found in the house.

They were eventually cleared of any wrongdoing and an apology was issued in 2008, leaving the murder unsolved and the killer still at large.

Now a former detective on the case says overlooked clues such as cobwebs and a child’s toy could be important.

In Foreign Faction: Who Really Kidnapped JonBenet Ramsey?, Jim Kolar examines thousands of pages of investigations.

He told the Daily Beast website that a children’s toy, rather than a stun gun, could be responsible for marks on JonBenet’s back.

JonBenet's father John Ramsay told police in 1996 that an intruder broke through a window in the basement.

But the Daily Beast reports that Mr Koler's investigation of a police video of the basement taken hours after JonBenet's body was discovered reveals cobwebs which he says would have been brushed away by an intruder.

He says this means the killer would have already been in the house.

Mr Koler has outlined his theories to Boulder authorities, the Daily Beast says.

But district attorney Mary Lacy, who apologised to the Ramsays over the police investigation which focused on them, has dismissed the Koler theories.

The murder drama began on Christmas Day 1996 when the Ramsays received a ransom note saying JonBenet had been kidnapped and would be killed unless a $118,000 ransom was paid.

The money demanded was the amount of a bonus Mr Ramsey had recently received.

The body was discovered soon after.