According to a report in New York Magazine, HarperCollins kept secret for months a new book by a man who claims to have irrefutable evidence that the never-captured Zodiac Killer is his father.

HarperCollins acquired story more than a year ago but kept the Zodiac Killer details quiet until today. The book, The Most Dangerous Animal of All, hits shelves tomorrow.

The new claim comes from Gary Stewart, a vice president at a Baton Rouge construction company, who apparently discovered the gruesome connection while searching for his birth father.

Fifteen months ago he approached the publishing house with his story and began co-writing the book with true-crime writer Susan Mustafa.

It's not the first time someone has publicly claimed they were fathered by the Zodiac Killer, but a HarperCollins publicist told New York Magazine that the company's lawyers vetted Stewart's claims and found them "legally sound."

She didn't share many details of the book, but told me that Stewart's father had a criminal record in San Francisco ("forgeries, bad checks"), and there was a strong resemblance between his father's mug shot and the police sketch.

Apparently, the police sketch was a good one. Said Andreadis: "If you look at Gary's photo next to the sketch of the Zodiac next to his father's mug shot, you can see that there is very clearly more than just a passing resemblance. They look alike."

The book's official description also cites the existence of forensic evidence.

[image via AP]