Cabot Peden spent a year in the Kuwaiti desert with Matthew Riehl, and not once did Peden get the sense that his fellow medic in the Wyoming National Guard one day would switch roles and take a life rather than try to save one — as he did Sunday in a deadly shootout with law enforcement officials at a Highlands Ranch apartment.

“From the time we went over to the time that we went home, I didn’t see anything that would indicate Sunday would have happened,” Peden said of their 2009-10 deployment as part of Operation Iraqi Freedom. “Medics are a bit of a special breed where we have generally an overwhelming desire to help the Joes.”

Like many of Riehl’s friends and acquaintances, Peden still is trying to understand what prompted him to start a firefight at his home that led to his death, the death of Douglas County sheriff’s deputy Zackari Parrish and injuries to four other law enforcement officers and two neighbors.

What several of Riehl’s associates with military backgrounds agree on, however, is that his time in the U.S. Army Reserve and the Wyoming Army National Guard was not an obvious driving force behind his downward spiral.

“I know that Matt was very well liked and well respected by the guys he trained to go overseas with,” said Peden, who shared a tent in Kuwait with Riehl and other medics for about nine months.

Peden said their primary assignment in Kuwait was escorting supply convoys in and out of Iraq, and that a typical mission involved an overnight trip. He wouldn’t say whether Riehl dealt personally with a wounded or dead soldier, but he generally described their experience as fortunate.

“You spend your year with a head on a swivel and you’re always wondering what is going to happen that night, but that’s a typical day,” Peden said. “We were pretty fortunate, because it was a pretty quiet year. We were relatively safe.”

Izaak Schwaiger, a Marine who went to law school at the University of Wyoming with the shooter, was left with a different impression of Riehl and his military career — which began in 2003 with the U.S. Army Reserve and ended in 2012 with an honorable discharge from the Wyoming Army National Guard, according to National Guard officials.

In an online post, Schwaiger wrote that Riehl approached him in 2007 with a desire to go hunting and get “his first kill.” Schwaiger turned him down — “there was too much of that kind of talk from wannabe soldiers,” Schwaiger noted — but later the two found themselves together on another hunting trip with a mutual friend.

“Matt showed up with a .300 WSM (Winchester Short Magnum), way more gun than any neophyte shooter has business shooting,” wrote Schwaiger, now a California attorney who specializes in police brutality cases. “And he couldn’t shoot it to save his life. Kept saying his optics were wrong, but he just didn’t know how to shoot.”

Schwaiger added: “There he was out there on the prairie — a small and puny kid with a thousand-dollar rifle that just wanted to kill something for the sake of killing it.”

But Schwaiger maintains that Riehl’s attack “had nothing to do with him being a veteran” and “everything to do with him being a puny, powerless eunuch flailing desperately through life in pursuit of an imagined manhood.”

Military officials said Riehl’s time in the service didn’t include any significant red flags, though the U.S. Department of Veterans Affairs noted he was given a 20 percent service-connected disability: 10 percent for a spinal problem and 10 percent for tinnitus, or a ringing in the ears.

Deidre Forster, a spokeswoman for the Wyoming Army National Guard, said she wasn’t aware of any discipline leveled against Riehl or any issues surrounding his service. She also said she didn’t know if he saw any combat.

“I’m not aware that he did,” Forster said. “I don’t believe he did.”

There are signs, however, that Riehl’s life began to unravel sometime around 2014.

That’s when he experienced a psychotic episode and was hospitalized at a VA facility in Wyoming for three weeks, during which time he briefly escaped. Following his apprehension, Riehl was placed on a 72-hour mental health hold.

About a year later there was an “urgent contact” for mental health, according to documents provided by the VA to Congress — though VA officials aren’t releasing details of either incident.

“VA cannot ordinarily discuss the specific care of any veteran without a privacy release,” VA spokesman Curt Cashour wrote in a statement.

It’s unknown whether the VA reported Riehl to the National Instant Criminal Background Check System, or if the agency even had to.

Wrote Cashour: “Veterans are reported to the National Instant Criminal Background Check System (NICS) if they are adjudicated as incompetent by the Veterans Benefits Administration for purposes of managing their monetary benefits.”

U.S. Rep. Mike Coffman, R-Aurora, said that’s a question he’s pursuing.

“I think I need to look at (what) was the responsibility for the VA to report this information and have it go into the database,” he said.

A Laramie gun shop owner called police Sunday after the shooting to report that Riehl purchased nine guns and two gun receivers, including a Plum Crazy AR-15 receiver with a magazine that can hold 100 rounds, a Laramie police report says.

David Smith, the owner of Dave’s Guns, said he did gun checks each of the 11 times he sold a gun to Riehl. He called police because he thought the information might help investigators. The gun purchases apparently came before Riehl was placed on the mental health hold.

Late last year there was an attempt by some of Riehl’s friends to get through to him — as he had posted a number of disturbing messages online. Leon Chamberlain, a retired behavioral health officer who knew Riehl from the Wyoming National Guard, was asked to reach out to him.

Helen H. Richardson, The Denver Post Elizabeth police officer Sean Bigler, middle, gets a hug from a fellow officer during a candle light vigil for her their friend and fellow officer Douglas County deputy sheriff Zackari Parrish at Mission Hills church on Jan. 1, 2018 in Littleton.

Helen H. Richardson, The Denver Post Officers and friends of slain Douglas County deputy sheriff Zackari Parrish hug one another during a candlelight vigil at Mission Hills church on Jan. 1, 2018 in Littleton.

Helen H. Richardson, The Denver Post Elizabeth police officer Sean Bigler, middle, cries with his wife and fellow officers by his side during a candle light vigil for his friend and fellow officer Douglas County deputy sheriff Zackari Parrish at Mission Hills church on Jan. 1, 2018 in Littleton.



Helen H. Richardson, The Denver Post Gracie Parrish, middle, holding her daughter Evie, rests her head in her hands, as she is overcome with emotion during a candlelight vigil for her slain husband Douglas County deputy sheriff Zackari Parrish at Mission Hills church on Jan. 1, 2018 in Littleton.

Helen H. Richardson, The Denver Post Douglas county sheriff deputies arrive for a candlelight vigil for slain Douglas County deputy sheriff Zackari Parrish at Mission Hills church on Jan. 1, 2018 in Littleton.

Helen H. Richardson, The Denver Post Volunteer Kim Lundquist, left, hands out candles before a candlelight vigil for slain Douglas County deputy sheriff Zackari Parrish at Mission Hills church on Jan. 1, 2018 in Littleton.



Helen H. Richardson, The Denver Post A Castle Rock police officer, wearing black over his badge, arrives for a candlelight vigil for slain Douglas County deputy sheriff Zackari Parrish at Mission Hills church on Jan. 1, 2018 in Littleton.

Helen H. Richardson, The Denver Post A makeshift memorial has started as people leave flowers on a police cruiser outside of the Douglas County Sheriff Substation for Deputy sheriff Zackari Parrish Parrish on Jan. 1, 2018 in Highlands Ranch.

Helen H. Richardson, The Denver Post People leave flowers on a police cruiser outside of the Douglas County Sheriff Substation for Deputy sheriff Zackari Parrish on Jan. 1, 2018 in Highlands Ranch. Parrish, 29, killed when deputies responded to a domestic disturbance at Copper Canyon apartment complex.



Helen H. Richardson, The Denver Post People embrace after leaving flowers on a police cruiser outside of the Douglas County Sheriff Substation for Deputy sheriff Zackari Parrish on Jan. 1, 2018 in Highlands Ranch.

Helen H. Richardson, The Denver Post Neighbors of Deputy Zackari Parrish placed blue ribbons on trees in honor of him on Dec. 31, 2017 in Highlands Ranch.

Helen H. Richardson, The Denver Post Sheriff deputies put up police tape around the scene of an early morning shootout that led to the death of a Douglas County sheriff deputy on Dec. 31, 2017 in Highlands Ranch.



Joe Amon, The Denver Post A gunman killed one Douglas County deputy and wounded four others during an early morning ambush as they responded to a domestic disturbance call at a Highlands Ranch apartment complex Dec. 31, 2017.

Helen H. Richardson, The Denver Post Police investigate the scene of an early morning shootout that led to the death of a Douglas County sheriff deputy on Dec. 31, 2017 in Highlands Ranch.

Helen H. Richardson, The Denver Post A tow truck driver secures the suspect's vehicle to his truck as police continue to investigate the scene of an early morning shootout that led to the death of a Douglas County sheriff deputy on Dec. 31, 2017 in Highlands Ranch. Deputy Zackari Parrish, 29, was killed and four other deputies were wounded in what police described as an ambush when deputies responded to a domestic disturbance at Copper Canyon Apartment complex at 3401 E. County Line Road.



Helen H. Richardson, The Denver Post Police investigate the scene of an early morning shootout that led to the death of a Douglas County sheriff deputy on Dec. 31, 2017 in Highlands Ranch. Deputy Zackari Parrish, 29, was killed and four other deputies were wounded in what police described as an ambush when deputies responded to a domestic disturbance at Copper Canyon Apartment complex at 3401 E. County Line Road.

Helen H. Richardson, The Denver Post Police investigate the scene of an early morning shootout that led to the death of a Douglas County sheriff deputy on Dec. 31, 2017 in Highlands Ranch.

Helen H. Richardson, The Denver Post Police investigate the scene of an early morning shootout that led to the death of a Douglas County sheriff deputy on Dec. 31, 2017 in Highlands Ranch.



Helen H. Richardson, The Denver Post Police investigate the scene of an early morning shootout that led to the death of a Douglas County sheriff deputy on Dec. 31, 2017 in Highlands Ranch.

Joe Amon, The Denver Post A gunman killed one Douglas County deputy and wounded four others during an early morning ambush as they responded to a domestic disturbance call at a Highlands Ranch apartment complex Dec. 31, 2017.

Joe Amon, The Denver Post A gunman killed one Douglas County deputy and wounded four others during an early morning ambush as they responded to a domestic disturbance call at a Highlands Ranch apartment complex Dec. 31, 2017.



Helen H. Richardson, The Denver Post Police investigate the scene of an early morning shootout that led to the death of a Douglas County sheriff deputy on Dec. 31, 2017 in Highlands Ranch. Deputy Zackari Parrish, 29, was killed and four other deputies were wounded in what police described as an ambush when deputies responded to a domestic disturbance at Copper Canyon Apartment complex at 3401 E. County Line Road. The gunman used a rifle and fired at least 100 rounds at the deputies. The gunman was killed in the shootout with law enforcement officers. Parrish is survived by a wife and two children. He had been a deputy for only 7 months. The other injured officers are Dep. Mike Doyle, 28, Dep. Taylor Davis, 30 and Dep. Jeffrey Pelle, 32. Castle Rock police officer Tom O'Donnell, 41 was also injured. All are listed as stable at area hospitals.

Joe Amon, The Denver Post A gunman killed one Douglas County deputy and wounded four others during an early morning ambush as they responded to a domestic disturbance call at a Highlands Ranch apartment complex. Dec. 31, 2017 in Denver.

Joe Amon, The Denver Post A gunman killed one Douglas County deputy and wounded four others during an early morning ambush as they responded to a domestic disturbance call at a Highlands Ranch apartment complex Dec. 31, 2017.



John Leyba, The Denver Post Police officers line up their patrol cars outside of Littleton Adventist Hospital for a procession honoring an officer who was fatally wounded in a domestic incident in a Highlands Ranch apartment complex on Sunday, Dec. 31, 2017.

John Leyba, The Denver Post Emergency personnel shield the cameras with a white sheet as they load fallen officer who was shot and killed during a domestic violence call in a Highlands Ranch apartment complex early Sunday. Various police agencies lined up for a procession for fallen officer on Dec. 31, 2017 in Littleton.

John Leyba, The Denver Post A bystander stands on the side of the road on S. Broadway holding an American flag as a procession leaves Littleton Hospital with fallen officer who was shot and killed during a domestic violence call in a Highlands Ranch apartment complex early Sunday. Various police agencies lined up for the procession on Dec. 31, 2017 in Littleton.



John Leyba, The Denver Post A hearse arrives at Littleton Hospital as officers from various police agencies line up for a procession for fallen officer on Dec. 31, 2017 in Littleton. One Douglas County deputy died and four more wounded along with two civilians Sunday morning at a Highlands Ranch apartment complex.

Before, Riehl “seemed like an easygoing kid,” Chamberlain said. “Conscientious and (he) got along with others.”

But when Chamberlain tried to contact Riehl last year, he said it “wasn’t the Matt that I remember.”

“He just responded with some real bizarre texts,” he said.

Those texts, and a later Facebook post, would compel Chamberlain to warn officials at both the University of Wyoming and the Converse County Sheriff’s Office in Douglas, Wyo.

From there, Chamberlain said he heard little else until learning about Sunday’s shooting and feeling the “shock and sadness.”

“I’ve been working for a counselor for a number of years,” Chamberlain said. “It would be nice to know what goes on in a person’s brain. Why do people do some of the things they do?”

Reporters Kirk Mitchell and Jesse Paul contributed to this report.