LA County Sheriff Robert Luna also released more details on the weapons used during the massacre.
MONTEREY PARK, Calif. (KABC) -- During an evening news conference Wednesday, Los Angeles County Sheriff Robert Luna provided new details on the investigation into the Monterey Park mass shooting that left 11 people dead.
He began by showing new photos of the weapons used by 72-year-old Huu Can Tran during the massacre.
Luna said Tran used what is commonly known as a Mac-10 to carry out the deadly shooting at the Star Dance Studio on Saturday.
Luna said that weapon was not registered in the state of California and said Tran purchased it in Monterey Park in 1999. Two other weapons, one used by Tran to take his own life and another that was found in his home in Hemet, were registered.
Tran's criminal record consists of an arrest in 1990 for unlawful possession of a firearm, authorities said.
Earlier Wednesday, Monterey Park Police recovered a motorcycle in the 200 block of S. Garfield Avenue, just one block south of the crime scene, that was registered to Tran.
"Homicide investigators determined that the motorcycle was parked there sometime on Saturday, just prior to the mass murder," said Luna.
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Investigators believe it was placed there by the suspect as an alternative getaway vehicle.
The motive for the shooting remains unknown, according to Luna, who said investigators have not been able to establish a connection between Tran and any of the 11 victims.
"The suspect was not married," said Luna in response to reports that Tran may have been targeting his wife. "We have not been able to tie him in, romantically, to any of victims so far."
Luna stressed that information may change. He also said Tran has not visited the dance studio in years, according to witnesses.
"Based on the statements we have, he hasn't been there in five years," said Luna.
According to the department's lead investigator, Tran was of Vietnamese decent.
"We're looking at everything," said Luna. "Every which way, with the goal of trying to find a motive, hopefully we can."
"Sometimes it's frustrating when something like this happens that's so tragic because we're trying to understand it, and it doesn't make sense," he said. "It really doesn't."