The shots were fired in less than eight minutes, claiming three lives after Rodger fatally stabbed his two roommates and their friend at his apartment.
"We believe during his brief rampage, Elliot Rodger fired more than 50 rounds of ammunition, changing magazines more than five times during the shooting spree," Brown told Santa Barbara County supervisors Tuesday.
Rodger, 22, died at his own hand, slumped behind the wheel of his smashed BMW with three semiautomatic handguns and 410 rounds of ammunition at his side, Brown said.
In those few minutes, Rodger left 10 crimes scenes in a single square mile.
Brown, who was reelected Tuesday by county voters, told supervisors that people are asking how it could have been prevented, KEYT-TV reported.
"Elliot Rodger was very clever and very adept at convincing people that he was functional and not a threat to himself or others," Brown said.
The Sheriff's Department has defended its handling of the Rodger case. Brown has said deputies acted properly, including during an April welfare check at Rodger's apartment.
The department had three interactions with Rodger in the year before the May 23 attack.
In January, Rodger accused his roommate of stealing three candles worth $22 and performed a citizen's arrest, officials said. The Santa Barbara County Sheriff's Department eventually arrested the roommate and booked him on petty theft charges.
Last summer, Rodger accused several people of assaulting him. But investigators concluded he was the aggressor, and a detective dropped the case.
On April 30, four deputies, a
The visit occurred after a person who identified himself as a friend of Rodger called a county mental health staff member. Based on that call and information from Rodger's mother, sheriff's officials said in a statement, the staffer requested the welfare check.
Sheriff's officials did not detail what information the deputies had when they made the visit. But a Rodger family friend told The Times his mother had contacted his therapist in April, concerned over bizarre videos her son had posted on YouTube.
The family friend said the therapist contacted a mental health service, which referred the matter to authorities.
When authorities conducting the check spoke to Rodger outside his apartment, the department said, he was "shy, timid and polite."
"Based upon the information available to them at the time," the statement continued, "sheriff's deputies concluded that Rodger was not an immediate threat to himself or others, and that they did not have cause to place him on an involuntary mental health hold, or to enter and search his residence.
"Therefore, they did not view the videos or conduct a weapons check on Rodger."
Officials said the department was never aware he had legally purchased three firearms. Brown told reporters that because Rodger had never been institutionalized or held by authorities, he was permitted to have the guns.
Rodger wrote of the April 30 sheriff's visit in a 137-page document. He wrote that he had three semiautomatic weapons hidden in his bedroom at the time and had written up plans for the assault.