NEWBURY PARK, Calif. – Sunny Southern California weather has a way of making all neighborhoods look idyllic.

But in one such Los Angeles-area home, a ranch-style house in a pleasant, leafy enclave, lurked a profound darkness. Inside 804 Fowler Ave. lived a troubled man whose rages created booming noises and summoned local police.

Marine Corps veteran Ian David Long, 28, the man accused of killing 12 at a nearby country bar late Wednesday before shooting himself, was a former machine gunner and decorated combat veteran of the war in Afghanistan who, authorities said, had an episode of erratic behavior last spring that suggested post-traumatic stress disorder.

Long's various interactions with police over the years pointed to a man who needed professional help. None came.

Neighbor Richard Berge said everyone on the block was aware when the police came to the Long home earlier this year after an incident.

“Police were here, and they finally get (Long) to come out of the house," Berge told USA TODAY Thursday as FBI agents shuttled in and out of the home Long shared with his mother, Colleen.

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Berge described Long's mother as “a very nice lady" – he got to know her after offering to care for one of the family's combative German shepherds – who was frustrated her son wasn't seeking help for his condition.

Although Berge had never been inside the Long house, he said a neighbor had reported seeing walls that were "full of holes," adding that the neighbor got the impression that Long had kicked the walls in.

“She was worried because he wouldn’t get help,“ Berge said. “I asked her, ‘Can’t he just get help.’ She said, ‘He can’t get help.’"

Longtime neighborhood resident Donald MacLeod, 79, shares a back wall with the Long residence. He says he often heard the volatile adult son arguing with his mother at all hours, sometimes “in the middle of the night, at 2 a.m."

MacLeod noted that Long was loud and appeared to be threatening violence. More than a year ago, MacLeod heard a gunshot in the home but did not call police. He said he viewed Long as troubled and kept his distance, adding that he told his wife to treat the young man carefully avoid any prolonged discussions.

“No question in my mind that the guy was troubled,” he said, adding that Ian Long’s time in Afghanistan “made it worse.”

McLeod said Long’s role in the mass shooting fit his impressions. “I’m not surprised at all,” he said. “I did not trust the guy.”

Tim Tanner, who lives on the corner three houses away, said Long was someone who largely kept to himself.

“I’ve seen him a couple of times,” he said. Long was easily identifiable when he drove around the neighborhood in his bright red pickup truck, which was still in the cordoned off driveway Wednesday.

He was a “quiet, normal guy, kept to himself.”

That "normal" characterization stands in contrast to a depiction by a former roommate of Long's who described him as a "weird" loner who could be aggressively anti-social.

“He was kind of weird, he always locked himself in his room, he was always by himself,” Blake Winnett, 35, told the New York Post. “I didn’t really know him very well.”

He should have. Winnett and Long lived together on two occasions in 2012 and 2014, while Long was attending college in nearby Northridge. But Long apparently was purposefully standoffish.

“He didn’t want to help anyone do anything, he was just lazy, I guess,” Winnett recalled. When Long was once asked to take out the trash, he snarled, “That’s not my (expletive) job."

Winnett said he saw no evidence of violence from Long. Instead, he says his roommate often would disappear into the garage where he would practice dance moves for hours on end.

"He would close the garage and be playing music and dancing in there, like sweating," Winnett said. "I would open the garage and would be like, ‘What are you doing?'”

Run-ins with local police

Local authorities said they had periodic contact with Long over the years.

He was the victim of a battery at a local Thousand Oaks bar and also had been involved in two traffic accidents. Deputies were called to his home last year because of a domestic dispute, where he was "somewhat irate and acting irrationally," said Ventura County Sheriff Geoff Dean.

However, after mental health professionals observed Long, they decided not to pull him in for further observation, Dean said.

Neighbors called to complain of loud noises earlier this year that sounded like he was damaging the house, neighbor Tom Hanson told local TV stations KTLA and KTTV.

"It sounded like he was tearing down the walls of the house," Hanson said.

The Marine Corps released a statement Thursday extending condolences to the victims and their families, noting that Long served from 2008 to 2013, including a 2010-11 stint in Afghanistan. He last post was at Kaneohe Bay in Hawaii.

The Marine Corps' commandant, Robert B. Neller, tweeted his "heartfelt condolences" to those impacted by the shooting, while pointedly distancing himself from the Corps' former member.

"That ex-Marine's despicable actions run counter to what the vast majority of veterans are rightfully known for: serving w/ honor then making positive contributions to society," Neller wrote.

Some of those responding to Neller's tweets brought attention to the general's use of "ex" as opposed to "former," while others asked the commandant to focus the Corps' attention on PTSD and general care for veterans.

Still others put a spotlight on Brendan Kelly, a former Marine who was a helpful hero during the Borderline shooting and had also survived the Las Vegas massacre last year.

Prior to joining the Marines, Long attended Newbury Park High School not far from the family home.

Scott Drootin was Long's baseball coach during Long's sophomore and junior years at Newbury Park, where Long had transferred into from rival school El Modena.

He described his player as a good athlete but not a star — and noticeably downbeat.

“He was a very intense person, he didn’t seem like a happy kid," said Drootin. "The coaches and I tried to get the players to smile and have fun. It was really hard to get him to smile."

That said, Drootin stopped short of calling Long dangerous. "There were no signs of him having an explosive personality."

Drootin did single out Long's mother as some who was devoted to her son. "She really loved him," he said, adding that Long's mother was very active at school and athletic fundraisers.

A Twitter account belonging to Megan Barnes, a Long Beach Press Telegram reporter, reported that a former baseball coach of Long's, Matt Goldfield, had found a 2007 baseball team program that offered details about his former player.

Among the photos of the program posted online, one was of what appears to be a paid ad in the program, purchased by Long's mother. The dedication reads: "I'll love you forever, I'll like you for always. As long as I'm living, my baby you'll be. Love, Mom."

Among the other photos were some of Long in uniform and at the plate. A page dedicated to the player reported him as being 6-foot-1 and 170 pounds.

Long's nickname is listed as Easy E, his batter-up song was "Don't Stay" by Linkin Park and his parents are listed as Colleen and David. He had no siblings.

Under "Home Runs," Long had listed snowboarding, trucks, GRAW and winning. GRAW is a common acronym for Ghost Recon Advanced Warfighter, a tactical shooter video game. His favorite movie was listed as United 93, the story of the passengers trying to take control of the doomed hijacked plane on Sept. 11, 2001.

Under "Strikeouts," he cited work, Volkswagens and crashing.

Long wrote that his plans after high school included college baseball and professional baseball. Under "After Baseball," Long wrote "Death."

While Long's destiny wound up being the military and not the Major Leagues, he did seem to find some semblance of a normal life in June of 2009, when he wed Stavroula Tzavaras in Honolulu, Hawaii, according to court records.

But the marriage didn't endure. The couple separated in 2011, and finally divorced in 2013 citing irreconcilable differences.

Ultimately, whatever demons lived inside Long compelled him to dress Wednesday in a black, hooded outfit and load his legally purchased .45-caliber handgun that had an extended magazine for extra bullets that is illegal in California.

Long then headed to the Borderline Bar & Grill in neighboring Thousand Oaks, about 40 miles northwest of Los Angeles, where he first shot security guards and then fired on hundreds of partiers who had gathered for the club's regular "college night" event.

A sheriff's sergeant rushing to the scene to help was among those killed. Long was found dead of an apparently self-inflicted gunshot wound lying not far from the entrance to the club.

Contributing: Brett Murphy and Jefferson Graham with USA TODAY; Kathleen Wilson and Tom Kisken, Ventura County Star