Since the shooting in a Monterey Park, California, dance hall on Sunday night, the victim death count has risen to 11, with 9 seriously injured. Law enforcement is slowly piecing together a motive for the tragedy, although it’s still early in the investigation.

“What drove a madman to do this? We don’t know, but we intend to find out,” Sheriff Robert Luna said in a press conference, per The Associated Press.

Police searched suspected shooter Huu Can Tran’s home in a senior community located in Hemet, where he lived alone, as reported by NBC News. Inside the home were thousands of rounds of ammunition and evidence of homemade silencers.

The suspect had visited the police station earlier this month to report being a victim of fraud, poisoning and theft from family members decades earlier, reported AP. But he had never returned to the station with the paperwork he said would prove it.

The targeted dancehall was also a part of the suspect’s history, as reported by CNN. Though his visits had been less frequent in recent years, he used to teach informal dance lessons to women at the dance hall, and it’s where he met his now ex-wife.

Around 2010, the suspect and a former close friend visited the dance hall frequently, per AP.

“He always cast a dubious eye toward everything,” the friend, who requested his name be kept away from the media spotlight, told AP. “He just didn’t trust people at all. He always complained to me that the instructors ... kept distance from him, and according to what he said, many people spoke evil of him.”

The investigation is currently still underway.

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