Currently in jail in Colorado, Keith Schwinaman was allegedly targeted by investigators after his ex-wife, Heather Kubes, reportedly confessed she 'couldn't recount' his whereabouts the night the six-year-old was fatally strangled inside her Boulder home in 1996.
But after 15 years, Schwinaman has now blasted his ex's insinuations that he was the killer in America's most infamous cold case.
The US publication claims Schwinaman asserts he 'didn't do it!'
In the letter, obtained by the National Enquirer, Schwinaman admitted: 'I was living in the area and committing crimes around the same time', but insists he had nothing to do with the beauty queen's murder.
The murder of JonBenet Ramsey remains a cold case to this day.
This article originally appeared in New Idea.