The man suspected of killing an Arizona sheriff's deputy and a vacationing New Hampshire couple in two separate incidents has been identified as 30-year-old Drew Ryan Maras.

The Maricopa County Sheriff's Office would not give further details about the accused, who was shot dead by deputies Sunday.

Local residents said Monday that Maras was a former Marine who later became an author with a passion for writing about UFOs, the Mayan calendar and the apocalypse, MyFoxPhoenix.com reported.

He was said to be the author of "Open Your Eyes To 2012 and Beyond," a book described on Amazon as "Your guide to navigating the revelation, and the Rosetta Stone for deciphering this once-every-25,800-year galactic alignment cycle set to commence on Dec. 21, 2012."

The book description identifies Maras as "Trained for war by the U.S. Marines Corps infantry and then turned pacifist."

His neighbors said the last time they saw Maras was soon after the new year. They believed he had been on his way to Colorado and then Hawaii to promote his latest book.

"I was going to go buy one and have him sign it before he left, then he left like a day early. I never saw him," Maras' neighbor, Alex Piper, told Fox affiliate KSAZ-TV. 

"It's just mind-boggling because he seemed like a normal guy," neighbor John Demarr said. "He seemed like a cool guy, just a normal guy, don't expect that from him."

Maricopa County Sheriff's Deputy William Coleman, 50, was shot Sunday morning while answering a burglary call at a medical building in Anthem, Ariz. He was taken to the hospital where he later died.

Investigators believe the gun used to shoot Coleman may have been used to kill James Johnson and Carol Raynsford, both 63 years old, near Sedona, Ariz., on Friday. The pair was visiting from New Hampshire, according to MyFoxBoston.com. 

The couple's vehicle was found on Route 89A in the central part of the state. Authorities said 223 shell casings, which are most commonly used in rifles, were found in the area. Coleman, like Johnson and Raynsford, was shot with a high-powered rifle, and the two homicide scenes are connected by the same stretch of highway.

Maras' neighbors told KSAZ-TV that he made frequent trips to Sedona.

Newscore contributed to this report.