The Monterey Park gunman was banned from the dance studio where he massacred 11, it is claimed.
Huu Can Tran, 72, was kicked out off Star Ballroom Studio and Lai Lai club around five years ago for being "too argumentative" and "pestering" women, according to members of the clubs.
Tran fired 42 rounds in the Star Ballroom Studio on Saturday night in California, US, killing 11 and wounding 9 during the Lunar New Year massacre.
Pinki Chen, who attends the Star Ballroom Studio, said the gunman was banned from the dance studios and hadn't been there for a number of years due to him "irritating" staff and students.
Chen told the Daily Mail: "When he would come to the dance halls, he would offer free lessons, but would tell the woman that in exchange she could only dance with him.
"Many of the dancers and teachers complained that he was argumentative and ultimately Tran was no longer allowed back to either Star Dance Studio or Lai Lai."
After opening fire in the dance studio, the gunman got into his van and 20 minutes later entered Lai Lai club but was quickly disarmed by a heroic member of staff.
Tran later shot himself in his van as officers discovered his body on Sunday morning.
According to police, the weapon he used in the horrific shooting was a Cobray model CM11-9. Officers also found a 308 caliber bolt action rifle at his home.
Tran, who was originally from Vietnam, bought the machine pistol in Monterey Park in 1999, but it was not registered in California, the sheriff said. The gun and the high-capacity magazine are illegal in California.
Luna said Tran used a registered semiautomatic handgun when he died by suicide.
Los Angeles County Sheriff Robert Luna said investigators are still trying to determine a motive for the massacre.
Luna said Tran used a registered semiautomatic handgun when he died by suicide.
Tran, who was of Vietnamese descent and lived in Hong Kong, had been in the US for seven or eight years.
Mr Luna said: "We have not been able to establish a connection between the suspect and any of the victims thus far."
It is unclear how long Tran had been planning the mass shooting or what motivated him to kill 11 people and injure 9.
"It doesn't make sense," Luna said. "It really doesn't."
Police confirmed they searched the gunman's house and came across dozens of paperwork and items which have been seized from his home along with the van which he used to flee the shooting.
Hundreds of people have left flowers and candles outside the locked gates of Monterey Park's Star Dance Studio.
Marlene Xu gathered with fellow dancers by a row of flower-framed photos of the victims. Xu said she danced at the studio four times a week and spent an entire day and night in tears after the violence.
“It’s hard for us because it’s a part of my life,” she said. “It’s like a part of your life is gone.”
Vice President Kamala Harris visited the memorial on Wednesday, adding her own bouquet, before heading to a senior centre to talk to relatives of the victims.
She stopped front of each of the large, rose-framed placards that contained photos or names of the victims at the memorial.
"Tragically we keep saying the same things," Harris said. "Can they do something? Yes. Should they do something? Yes. Will they do something? That is where we all must speak up."
Pope Francis was among those offering condolences, saying in a message to the Los Angeles archbishop that he "implores the divine gifts of healing and consolation upon the injured and bereaved."
