A man who describes himself as a longtime friend of suspected California mass shooter Huu Can Tran has revealed that the 72-year-old offered free lessons at the Star Ballroom Dance Studio in search for a new dance partner after divorcing his wife, yet complained that the people there did not like him. 

The revelation comes as investigators Tuesday are still trying to determine what motivated Tran to open fire at the dance hall in Monterey Park Saturday night, killing 11 people and wounding nine, police say. An attempted attack by Tran at the Lai Lai Ballroom in Alhambra afterwards was thwarted by an employee there before the suspect was found dead of a self-inflicted gunshot wound in Torrance on Sunday. 

The friend who spoke on condition of anonymity to The Associated Press said Tran had offered to teach new women at both clubs how to dance for free so that he would have a partner after separating from his wife. 

"He always cast a dubious eye toward everything. He just didn't trust people at all," the friend said. "He always complained to me that the instructors... kept distance from him, and according to what he said, many people spoke evil of him." 

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California mass shooting suspect Huu Can Tran

Huu Can Tran, 72, was discovered dead on Sunday of a self-inflicted gunshot wound. (Los Angeles County Sheriff's Department)

Tran’s ex-wife told CNN they married soon after they met at Star Ballroom, where he offered her free lessons as well. She said he would become upset if she missed a step dancing, but was never violent toward her. 

They divorced five years later, citing irreconcilable differences, Los Angeles Superior Court records show. The couple did not have children, said they had no community property and neither side had to pay alimony. 

Authorities have shared little about Tran, who owned a trucking company in Monterey Park from 2002 to 2004, according to California business records. 

He was once arrested for unlawful possession of a firearm in 1990 and had a limited criminal history, Los Angeles Sheriff Robert Luna said. 

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Monterey Park mass shooting victims memorial

Yolanda Gallegos, 72, prays for victims killed in a shooting outside Star Dance Studio in Monterey Park, California, on Monday, Jan. 23. (AP/Jae C. Hong)

"What drove a mad man to do this? We don’t know, but we intend to find out," Luna said Monday. 

Sheriff’s deputies from Los Angeles County have searched Tran's home in a gated senior community in the town of Hemet, a little over an hour’s drive from the site of the massacre. 

Luna said his officers found a .308-caliber rifle, an unknown amount of bullets and evidence he was making homemade firearm suppressors that muffle the sound of the weapons. 

Tran had visited Hemet police twice this month to report he was the victim of fraud, theft and poisoning by family members a decade or two ago in the LA area, Hemet police spokesperson Alan Reyes told The Associated Press. Tran said he would return to the station with documentation but never did. 

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California mass shooting Monterey Park

Investigators leave the Star Ballroom Dance Studio following Saturday's fatal mass shooting in Monterey Park, California. (AP/Jae C. Hong)

A neighbor of Tran’s in Hemet told Fox11 Los Angeles that he "wasn't someone I'd be afraid of."    

"Everyone around him thought he was just a quiet little guy," Pat Roth told the station. "People I talk to are just stunned he was involved in this. Just kept to himself. We'd see him out [walking], but he pretty much lived alone."  

The Associated Press contributed to this report.