In 1992, a retired federal agent from Brunswick saw a notice in a local newspaper.

Trial and Error, the group of people who believe Dennis Dechaine was wrongfully convicted for a murder in 1988, was holding a meeting in town.

James P. Moore, a private investigator who had retired in 1985 from the U.S. Bureau of Alcohol, Tobacco and Firearms, recalls thinking that the group was likely a “bunch of birdbrains.” Out of curiosity, though, he attended the meeting.

By the end of that evening, Moore agreed to look into the case, with one caveat.

“I told them if I found more evidence that he is guilty, I’m giving it to police,” Moore said.

He began by reviewing the 1,500-page trial transcript. Moore was initially struck by the testimony of the deputy state medical examiner, who could not rule out the possibility that Sarah Cherry was killed after Dechaine was in police custody.

Other elements of the case concerned Moore: the lack of physical evidence and the fact that police did not pursue leads on other suspects, including a known child rapist who lived down the road from the house where Sarah Cherry had been abducted.

For the next 15 years or so, Moore devoted a significant part of his life to the investigation of the case, and he became one of Dechaine’s fiercest advocates.

“You have some poor guy in jail that didn’t do anything,” Moore said in an April 26 interview. “I couldn’t let go of it.”

In the fall of 2002, Blackberry Press published Moore’s book, “Human Sacrifice.” Moore’s central claim was that Dechaine could not have committed the crime and had been set up by another man. Moore contended that police and prosecutors, in their single-minded belief that Dechaine was guilty, ignored other leads, manipulated witnesses and withheld police reports from Dechaine’s lawyers before the trial.

The book sparked a renewed public interest in Dechaine’s case, and it swelled the ranks of Trial and Error. A revised version of the book was published in 2006, after Moore filed a lawsuit against the state Attorney General’s Office and gained access to the investigative files.

Moore said he did not accept payment for his work as an investigator or as a writer. He also has received none of the royalties from “Human Sacrifice,” which retailed at $15 and has sold more than 10,000 copies. Profits from the books have gone to Trial and Error, Moore said.

He said he decided a few years ago to cut down his advocacy work on the case, and to let Dechaine’s lawyers go about their business of seeking a new trial.

In response to the book, the lawyers at the Attorney General’s Office have said the evidence led to Dechaine, and to no one else, because he kidnapped, tortured and murdered Sarah Cherry.

Eric Wright, the prosecutor who represented the state at Dechaine’s trial in 1989, now works as an attorney for the Maine Bureau of Consumer Credit Protection. He declined to comment for this story. But Wright did respond to Moore’s book in 2003 in a newspaper article published in the Lewiston Sun Journal.

“Moore goes so far as to suggest, though not with proof, that the trial justice was unfair; that the Maine Supreme Judicial Court did not give this case any more than cursory review; that Mr. Dechaine did not stand a chance against a self-protective, clubby legal profession; that the state’s deputy chief medical examiner was incompetent, subject to manipulation, or a liar; that a dozen or so detectives and deputies from the Maine State Police and the Sagadahoc County Sheriff’s Office were either bumblers or conniving co-conspirators in repeated perjury,” Wright wrote in a five-page letter to the Sun Journal.

“This is no more than savaging good people for sport,” he wrote.