Local attorney Jason Moss, who as a University of Nevada, Las Vegas student turned his obsession with serial killers into the best-selling book "The Last Victim," killed himself in his Henderson home last week, authorities said.

Moss, 31, died June 6 after shooting himself in the head in a home bathroom, according to the Clark County coroner's office.

"There is nothing to suggest anything except suicide," Henderson police spokesman Keith Paul said.

In 1999, Moss landed on the New York Times' list of the nation's top-selling books with "The Last Victim," a graphic tell-all about his close encounters with infamous serial killers, including John Wayne Gacy, Jeffrey Dahmer, "Night Stalker" Richard Ramirez and Charles Manson.

Friends were asking Monday if there was significance in Moss' decision to kill himself on 6/6/06, a date similar to 666, which is said to be the "Number of the Beast" in the Bible's Book of Revelation.

Moss studied devil worship as preparation for beginning correspondence with the imprisoned Ramirez, a Satanist.

"It struck me that he did it on 6-6-6. I wonder if it was coincidence or if he planned to do it on that day for a reason," said counseling professor Jeffrey Kottler of California State University, Fullerton, Moss' co-author on "The Last Victim."

"He's not particularly religious, but he got heavily into Satanic stuff while doing the book," Kottler said. "He studied it but seemed to laugh it off."

When he was 19, Moss used trickery to develop pen-pal relationships with the murderers, portraying himself in letters to them as a worshiper or a victim that fit each killer's fantasies, leaving false clues about his sexual preferences, Satanic devotions and vulnerabilities.

The most intense relationship Moss forged was with Gacy, who killed 33 young men and boys, having sex with most of them before strangling and burying them in the crawl space of his Illinois home.

The book describes Moss' visit to Gacy in prison only two months before the killer's 1994 execution, an encounter during which Moss claimed he was almost raped by the notorious "killer clown."

Moss said in a 1999 interview with the Review-Journal that frequent nightmares of the two days he spent with Gacy began to fade only when he began telling people his story. He turned his experiences and insights into a thesis for the UNLV Honors Program. After more than 100 people showed up to hear his presentation, one of his professors urged him to turn the project into a book.

"The Last Victim's" lurid copy, including sexually explicit letters from Dahmer and Gacy, led to it selling by the truckload only days after its publication. The hardcover racked up 76,000 sales in its first 10 weeks of release.

Sales were boosted by controversy over Moss' methods. Readers were divided on whether the book was a useful examination of criminal psychology or a questionable exploitation of some of the most ruthless killers in history.

Moss landed on a variety of nationally broadcast shows, from TV's "20/20" and "Hard Copy" to radio's "The Howard Stern Show."

After graduating summa cum laude from UNLV, Moss collected a law degree from the University of Michigan and returned to Las Vegas. He entered private practice as a criminal defense attorney after interning with the Clark County Public Defender's office for two years.

Kottler said he last spoke to Moss a few weeks ago to discuss the annual reselling of the rights to turn "The Last Victim" into a movie. Hollywood mogul Merv Griffin has held the option to make a film adaptation for several years, but has not moved forward with production.

"He sounded harried and busy. He had talked about being excited about doing litigation, that he still hadn't lost a case" Kottler said. "I keep replaying the conversation in my head: did I miss a cry for help? But I can pretty vividly recreate that conversation and it was Jason as usual."