The cause of Relin's death on November 15 was listed as suicide by blunt force head injury, said Tom Chappelle, Multnomah County deputy medical examiner, but he declined to give further details. Relin, who lived in Portland, was 49.
Relin, a freelance journalist who wrote for several magazines, became best known for his work with Greg Mortenson on the wildly successful memoir "Three Cups of Tea," which was first published in 2006 and spent four years on the New York Times bestseller lists.
The book, which sold over 4 million copies, chronicled Mortenson's failed attempt to climb the mountain K2 in South Asia and his encounter with impoverished Pakistani villagers whom he credited with inspiring him to build schools for young girls and other humanitarian projects in the region.
However, the credibility of the book came under fire in 2011 when the CBS television news program "60 Minutes" aired an expose accusing Mortenson of fabricating or embellishing key details of his story, and using his charitable institute to promote sales of the memoir.
CBS News, for example, disputed Mortenson's account of being kidnapped in Pakistan's Waziristan region in 1996.
Mortenson later acknowledged in an interview posted on his institute's website that the book contains "discrepancies" that resulted from "omissions and compressions" done for the sake of literary expediency. But he insisted the abduction story was "pretty much" true and defended the book overall, saying, "I'm not a journalist. I don't take a lot of notes."
Relin said in a 2008 interview with a University of Oregon professor that in addition to interviewing Mortenson extensively, he conducted more than 200 interviews with people tied to Mortenson's story and traveled three times to northern Pakistan. Relin said he objected to Mortenson getting a co-author credit on the book.
Relin later wrote "Second Suns: Two Doctors and Their Amazing Quest to Restore Sight and Save Lives," which is scheduled to be released by Random House in June.
A graduate of Vassar College and the Writers' Workshop at the University of Iowa, Relin focused for two decades on reporting about social issues and their effect on children, according to an Iowa Writers biography.
In 1992, he received a University of Iowa fellowship to take a bicycle trip across the length of Vietnam and report on that country's economic reforms. The biography said he also won more than 40 national awards for work as an editor and writer, and that his stories about child soldiers were including in Amnesty International reports on the subject.
(Editing by Steve Gorman and Eric Walsh)