Gary Gauthier begins his letter with three words that echo woefully through all the world’s prisons and jails.

“I am innocent.”

And so begins a five-page diatribe in which the convicted double murderer condemns the jury that found him guilty, the media, his co-defendant and the two men he killed.

As inmate letters go, this one is particularly complete. There is a long section of declared innocence. There is a page or so filled with harsh words for the dead men and their families. There are vows to appeal the conviction and to one day walk again as a free man.

The letter is coherent and angry, defiant and indignant.

Gauthier is one of two men accused of killing John Graffam and James Vining shortly before Halloween in 2005. He was named as the man who tasted the blood of one victim before shoveling both into shallow graves.

And he writes from the county jail, awaiting his fate at a bigger prison, to insist that he is not guilty of any of it. He is the third victim, an innocent man ensnared in a plot so intricate that it fooled everyone.

Every time I read one of these letters, I pause for objectivity. What if, I wonder. What if this is truly an innocent man, screaming of the injustice but finding no believers. I’ve seen “Shawshank” a time or two. I know it happens.

“I am innocent. My co-defendant Tom Dyer lies,” Gauthier wrote “and friends and family members to the victims in this case, opinions to the media, are the reason I am convicted of murders I did not commit.”

He writes with bitterness about the newspaper articles and television clips showing grieving family members recalling their lost loved ones. Gauthier does not pretend to show sympathy. In his thoughts, the victims who were bludgeoned and kicked to death are as big a part of the conspiracy as their gushing friends.

“These were not upstanding citizens, they were drunks, bums who have hurt many people and committed many crimes,” he wrote. “James Vining was known as a very mean drunk and neither men were family people … Everyone talks about how John Graffam was on disability. I’m on disability for a severe anxiety and bipolar depression disorders. I grew up in an emotionally and physically abusive household.”

Those comments will sound familiar to anyone who listens with rapt fascination to a prison interview: I am the victim here. I’ve had it tough from the start and look at me now.

Gauthier may be going away for the rest of his life, but don’t credit brilliant police work or a marvelous prosecution. There was a time when bets were on an acquittal. With neither Gauthier nor Dyer speaking about the case, the jury only got to listen to DNA evidence and other bland details that droned on and on.

Then one of the defendants blinked. Tom Dyer got on the stand and told his version of the story. Predictably, he placed all blame on Gauthier, while describing enough of his own actions to incriminate himself. Both defense cases self-destructed.

If nothing else, Gauthier is entitled to anger toward his one-time friend. If Dyer and his lawyer had not gone on the offensive, both suspects might be sitting in a pub and giggling over the acquittal this very night.

“… because I don’t believe in snitching, and no one’s man enough to do right and take their own medicine, I am the third victim in this tragedy,” Gauthier wrote. “Tom Dyer is a liar, getting others to lie for him and trying to save himself from deserved punishment.”

Gauthier will be sentenced on Jan. 11. He will be sent to a state prison where a larger population of convicted men roam the sunless halls raving endlessly about their innocence. Understandably, Gauthier is not ready to join that world. He wants a new trial. He wants a chance to speak his mind, after all that silence.

“I will fight this conviction until my innocence prevails,” he wrote. “It’s a horrible story that’s far from over and won’t be until Tom Dyer washes his hands of his sins and comes clean, so justice can be properly served.”

Near the end of his letter, Gauthier takes time to express love, admiration or appreciation for many people: his new wife, his family, and at last, the families of the victims. He thanks his lawyer and the judge who presided over his case.

But there is also a solemn tone of finality, like a man who sees the approach of doom and is only beginning to believe that it is real.