Leaflets bearing anti-Semitic messages were placed on windshields of cars at the Lafayette BART Station parking lot by a man wearing a Santa Claus hat who threatened to kill a bystander attempting to stop him, police said Thursday.

BART police investigators plan to ask the Contra Costa County district attorney’s office Friday to charge the man with disturbing the peace, stemming from the “confrontation” that prompted the threat, a spokeswoman for the transit agency said.

Police did not identify the suspect.

Disturbing the peace — or the intent to use words to provoke a violent reaction — can be classified either as a misdemeanor or a lesser infraction under California state law.

The pamphlets — bearing the Star of David and covered in nonsensical anti-Semitic ramblings that referred to a “race war” — were reported to police by passersby on Tuesday and Wednesday. The flyers also contained barcodes linking to a series of racist website.

By Thursday afternoon, almost all of the flyers were gone, and a BART employee said a crew with the transit agency had swept up the stragglers earlier that day.

The distribution of the flyers left some residents of the East Bay community outraged and blaming the act on racial tensions throughout the county, some of it brought to a head by the presidential election.

“It’s all this rhetoric that’s going around on Facebook and wherever. Actually, this is now spilling out into the real world, into real life and it’s threatening and scary,” said Lafayette resident Eva Woo, as she entered the BART station.

Jeremy Russell, the head of communications for San Francisco’s Jewish Community Relations Council, said “it’s a chicken or an egg kind of question” of what causes such overt racism. But the effect matters more than the cause, he said, especially on Jewish people who live in the neighborhood.

“People who live near a place where they’ve been targeted by this kind of hateful speech are definitely going to feel a loss of safety and a sense of discord, and it’s really unfortunate to have to face that in your home,” Russell said.

While BART police are investigating the alleged death threat reported Wednesday by a BART rider who tried to stop the man from placing the leaflets on car windows, a spokeswoman for the agency said the act of distributing the pamphlets was protected under the First Amendment.

The pamphlets themselves are a free speech issue that transit police can’t interfere with, said Alicia Trost, a BART spokeswoman, citing a California appellate court ruling that protects the leaving of flyers on cars parked on public property.

“Appellate court case law rules leafleting free speech material on windshields is allowable and we cannot prohibit it,” Trost said in a statement. “There is no legal basis for us to intervene with leafleting alone even with hate speech.”

Seth Brysk, regional director for the Central Pacific branch of the Anti-Defamation League, said he’s “deeply unsettled and troubled” by the hateful act, adding that it’s one of several recent instances of discrimination around the Bay Area, including the July dissemination of KKK recruiting flyers in San Francisco.

The local ADL branch is assisting police in their investigation, Brysk said, adding that though it can be understandably tempting for bystanders to intervene when they see someone spewing out racist propaganda, that can do more harm than good.

“It’s really important that when the public encounters these types of things that they do not interact directly with the person who is doing it, that they contact law enforcement,” Brysk said. “If you’re a member of a targeted group and somebody is distributing information that’s hateful, that’s disparaging to your group, it’s understandable to have a reaction. But nobody should be taking the law into their own hands.”

The flyers also contained barcodes linking to a series of racist websites. The leaflet are similar in style and content to a blog targeting Jewish individuals in and around Lafayette for harassment, even singling them out by name.

“Doesn’t he have a life?” Lafayette resident Armand Doroodian said in response to the individual who passed out the flyers. “Is he a loser?”

Another local, Nataliya Kobal, said she has a host of Jewish friends from Russia and Ukraine who came to the United States to escape religious persecution years ago and were “looking for freedom here.” The flyers “disgust” her, she said.

“Wow,” she said, thumbing the glossy texture of one of the pricey-looking pamphlet. “Somebody actually paid money to print these?”

Michael Bodley is a San Francisco Chronicle staff writer. Email: mbodley@sfchronicle.com. Twitter: @michael_bodley