Ian David Long's neighbors described the man who reportedly killed 12 people in a country bar in Thousand Oaks, California, as a distant public, but fighting with his mother in the house they both shared.
A discussion in April was so extreme that several neighbors had to call the police. Authorities brought in a mental health specialist who concluded that Long could not involuntarily undertake psychiatric observation, but feared that the 28-year veteran of the Navy might have a post-traumatic stress disorder.
Julie Hanson, who lives next to the house of Long, described him as "strange" and "disrespectful" long before he left the house ten years ago, married and entered service with the Marine Corps and became a shooter.
She often heard him scream and swear, but a few months ago the unusually loud screams and shouts caused her husband to call the authorities.
"I was worried because I knew he had been in the army," Tom Hanson said on Thursday when law enforcement officers searched Long's home.
Hanson described Long as an introverted person and said he was "stunned" to learn more about the massacre.
In addition to the call in April, Long's only contact with the authorities after a traffic accident and after claiming that he was a victim of a violent meeting at another bar in Thousand Oaks in 2015, the sheriff said.
Long joined the marines at the age of 18 and married when he was 19 in Honolulu in June 2009, according to military and judicial records.
His military service lasted almost five years, and he was discharged with tribute with the rank of corporal in 2013, the Pentagon said. He was part of the infantry and was responsible for transporting and firing machine guns.
During his military service, Long's marriage broke up. He and his wife divorced each other in June 2011, during a seven-month tour in Afghanistan. The couple mentioned irreconcilable differences in the divorce documents filed in May 2013, two months after Long had left the Marine Corps.
Later he enrolled at the nearby California State University, Northridge, where he was last present in 2016, the school said in a statement.
More recently, he lived in a house where neighbors said they could hear frequent and aggressive shouts between Long and his mother, especially during the past year.
About 18 months ago, Don and Effie MacLeod heard "a terrible argument" and what he believes was a picture of the Longs property. Don MacLeod said he had not called the police but avoided talking to Ian Long. "I said to my wife:" Be polite to him. "When he speaks, just nod and do not talk to him," Don MacLeod said Thursday.
Few pictures on social networks showed a happy family. Long's mother, Colleen, placed Facebook photos of her son in his military uniform in 2010 and 2011.
"My son is home, well, back in Hawaii, and soon we will be in Cali in January, hurray!" He wrote on December 14, 2012.
Another picture from 2014 shows Ian Long with his arm around his mother in front of the Dodger stadium. They both wore T-shirts and smiled from the Dodgers.
Authorities have not identified what inspired Long to fire at Borderline Bar and Grill at Thousand Oaks, about 40 miles from downtown Los Angeles. Among the dead were 11 people in the bar and an experienced sheriff of the sheriff who was the first agent to cross the door.
The Marine Corps said that Long won several prizes, including a tape for combat action and a good behavioral medal from the Marine Corps. He was assigned to the 2nd Battalion, 3rd Marine Infantry Regiment, Third Marine Infantry Division at Kaneohe Bay, Hawaii.