Aaron HernandezThe man known only as “Karl” claims he never intended for the letter he received from Aaron Hernandez in jail to become public and now regrets selling the letter.

In a brief, eyebrow-raising interview with The Names Blog on Boston.com, Karl says he never thought the letter would show up online — at least, not the way it did.

“I don’t like the way it got out,” Karl said. “I wrote [Hernandez] last night because I don’t want him to think it was all about money.”

The incredibly naive “Karl” might not like the response he gets back from Hernandez. He is already receiving threats from Hernandez fans, Karl tells Boston.com, but that’s his problem now.

A letter from Hernandez proclaiming his innocence was posted Thursday on TMZ. The celebrity gossip site reportedly purchased the letter from Saugus, Mass.-based Sportsworld, which purchased the letter from Karl for significantly less than the $18,000 Sportsworld received from TMZ. Sportsworld owner Phil Castinetti was unapologetic in  his comments to Boston.com, saying “if it’s not me selling it, it’ll be someone else, so why not?”