All crime reporters have a story from their past they cannot shake, a case that either touched them on a profound personal level or remains mysteriously unsolved.

This time of year, I think of a story I covered 20 years ago this week, which remains with me for both reasons: the Christmastime death of 6-year-old JonBenét Ramsey in Boulder, Colo. As the mother of a daughter, I can’t help it. Every year, visions of JonBenet’s beautiful face and her obvious potential come flooding back to me.

Ahead of the sad anniversary of her Dec. 25, 1996, death, you probably noticed a flood of articles, programs and amateur conclusions about the case, each mentioning a mysterious 2½-page handwritten ransom note the Ramseys say was left behind by the killer (or killers).

That is the one piece of evidence I think is a key to solving the crime. (Another prime bit of evidence is the unknown DNA of a male left behind on JonBenét’s panties and pajama leggings. But so far, no suspect has emerged. More sophisticated DNA testing is expected soon.)

The phrases and words in the ransom note provide tantalizing clues as to its authorship, and some forensic document examiners have opined that it was likely written by a woman. Nurturing phrases like “I advise you to be rested” are what experts call “​maternalistic” language. They report finding six such statements in the note.

Before her 2006 death, JonBenét’s mother, Patsy Ramsey, vehemently denied she wrote it.

Various forensic examiners and various television networks have ruled out JonBenét’s father, John Ramsey, as the author of the note. They have also concluded that Patsy could not be excluded as the writer — this after they compared the note with extensive handwriting samples the couple provided for police shortly after the murder.

Additionally, the tablet the note was written on and the pen used to write it were identical to items discovered inside the Ramsey home. And a “practice draft” of the letter was found crumpled up nearby.

Retired FBI profiler Jim Clemente recently hosted a CBS special on the case, and his experts determined it would have taken more than 21 minutes for someone to write that lengthy note, which is “21½ minutes that they stayed in the house longer than they needed to.”

That’s not typical criminal behavior.

I recently spoke with Cina Wong, one of the forensic examiners who has studied the ransom note extensively. In 2000, the Ramseys’ lawyer got her disqualified from testifying on behalf of a man who filed a $50 million defamation case against them after they named him as a suspect in their book, The Death of Innocence.

But Wong is imminently qualified; she has become internationally recognized during her 25-year career and has testified under oath in some 60 cases. She is writing a book to lay out her findings on the Ramsey case and how she reached them. Her discoveries are persuasive.

First, after studying the awkward-looking writing at the beginning of the note, Wong says she saw that the writing style changed after the first few paragraphs. This, she says, is evidence the writer was deliberately disguising his or her handwriting.

Wong then referred to a “master pattern” chart that listed all the different ways the author wrote each letter. She noticed the writer’s distinctive letter “q” looked just like the number 8, and there was unique spacing of letters within certain words.

“Basically,” she told me during a phone call, “whoever has handwriting that matches all of these patterns is your ransom-note writer.”

Interestingly, Wong says, the master pattern was developed by the Ramseys’ own handwriting expert for the above-mentioned lawsuit, and the 101 pages of the Ramseys’ handwriting samples came from their attorney.

Wong quickly determined that John Ramsey’s writing had no similarities to the ransom note. Patsy, on the other hand, wrote the letter “c” in a compressed way that almost resembled the point of an arrow. The same was seen on the ransom note.

Patsy wrote five distinctly different styles of the letter “e,” and all five were seen on the ransom note. Patsy penned three different styles of the letters “a,” “d” and “h,” and all were seen on the ransom note. Patsy’s letter “q” looked just like the number 8.

“In all, I found 200 similarities between Patsy Ramsey’s handwriting and the ransom note,” Wong told me.

Does that mean Patsy Ramsey is, indeed, the person who wrote the note? Experts like Wong don’t speak in absolutes. She only said, “It is highly probable that she wrote the ransom note.”

Make of that what you will.

The mystery continues, and justice for JonBenét Ramsey remains elusive.

— Diane Dimond is the author of Be Careful Who You Love: Inside the Michael Jackson Case. Contact her at [email protected], follow her on Twitter: @DiDimond, or click here to read previous columns. The opinions expressed are her own.