GRANTS PASS, Ore. – David Oliver Relin, co-author of the best-selling book “Three Cups of Tea,” said in legal filings about a year before his recent suicide that his career suffered from allegations of lies in the story of a humanitarian who built schools in Pakistan and Afghanistan.

Relin committed suicide in the rural community of Corbett near Portland last month, the deputy Multnomah County medical examiner, Peter Bellant, said late Sunday. He was 49.

Relin died of a blunt force head injury on Nov. 14, Bellant said. He declined to provide other details. Relin’s family also declined to provide details of his death.

The book, which has sold about 4 million copies since being published in 2006, describes how Greg Mortenson, the other co-author, resolved to build schools for Pakistani villagers who nursed him to health after a failed mountaineering expedition.

The account came under scrutiny last year when “60 Minutes” and writer Jon Krakauer said it contained numerous falsehoods.

In April, a U.S. district judge rejected a lawsuit by four people who bought “Three Cups of Tea,” dismissing claims that the authors, the publisher, and a charity associated with the book conspired to make Mortenson into a false hero to make money.

In an August 2011 court filing, Relin attorney Sonia Montalbano said the lawsuit “has had a negative impact on Relin’s livelihood as an author” and that he did not “maintain any insurance for this litigation, which means that he has to personally fund his defense.”

In another filing, Montalbano said “Relin takes no position on many of the accusations made by the plaintiff” but “does stand by the manuscript he wrote.”

She pointed out that in an introduction Relin wrote for “Three Cups of Tea,” he “fully acknowledged potential inaccuracies.” Relin wrote that Mortenson’s “fluid sense of time made pinning down the exact sequence of many events in this book almost impossible.”

Relin “understood the potential importance of that story — that it could show that building schools was an antidote to just dropping bombs on that part of the world,” said Lee Kravitz, who introduced Relin and Mortenson.

Relin “was very committed to this project,” said Elizabeth Kaplan, the agent who represented both authors. “David seemed to understand Greg and his mission,” she said.

Following allegations that parts of “Three Cups of Tea” were made up, Mortenson denied any wrongdoing, although he acknowledged some of the events were compressed over different periods of time.

“Three Cups of Tea” was conceived as a way to raise money for and tell the story of Mortenson’s Central Asia Institute, which he co-founded in 1996 to build schools in Central Asia.

Relin interviewed Mortenson, attended several of his lectures and read previous articles before preparing a book proposal that was bought by Penguin Group. Relin then conducted more interviews with Mortenson and others before writing the manuscript, Montalbano said.