OAKLAND — A weekend of chaotic sideshow activity that culminated in four Oakland officers fatally shooting a man accused of pointing a replica pistol at them has local leaders considering another crackdown on the infamous illegal car shows.

Oakland police and California Highway Patrol officials promised increased enforcement after both agencies were overwhelmed by an estimated 700 joy-riders — some coming from as far away as Los Angeles — speeding through East Oakland neighborhoods and turning intersections and even Interstate 880 into a playground for motorcycle and car tricks.

Oakland Police Chief Sean Whent said rainfall finally put an end to the mega-sideshow, which turned violent before petering out around 4 a.m. Sunday. Sideshow participants fired at a CHP helicopter, pelted police officers with rocks and bottles, and were videotaped stomping on an Oakland patrol car, which was badly damaged. Only two people were arrested, both by the CHP, authorities said.

“Obviously it’s lawlessness,” Whent said at a Monday news conference.

The lawlessness picked up again Sunday as police were pulled from an Oakland Raiders game to quell two smaller sideshows in East Oakland.

As officers were writing up reports at the intersection of 90th and Bancroft avenues after stopping several motorcycles and ordering them towed, Whent said they were approached by a 39-year-old Oakland man who brandished a pellet gun designed to look like a real pistol. A sergeant and three officers fired, killing the man.

“The person didn’t say anything, and the officers just reacted to what they saw,” Whent said.

Police attributed the size and intensity of the weekend’s sideshows to a gathering of out-of-town motorcycle enthusiasts and car clubs, whose members also participate in sideshows.

Whent said authorities were aware of the motorcycle rally Saturday and assigned additional officers, including the department’s entire swing shift, to deal with it. However, authorities weren’t equipped to deal with 700 cars also participating in the sideshow being promoted on social media.

“It’s something that we’re trying to get better at,” said Whent about monitoring the Internet for potential sideshow activity. “Obviously it helps staffing-wise if we’re able to plan for it. In the middle of the night, it’s tough to muster a lot of resources.”

The presence of so many outside participants was especially infuriating to city officials, who have been dealing with the illegal car rallies for two decades.

“For some reason Oakland has been selected as a playground for irresponsible people from around the state,” Oakland Mayor Libby Schaaf said at the news conference. Schaaf said she will work with police on ways to curtail sideshows. On Monday, the city unveiled a sideshow tip line, asking people to call 510-777-8703 or email stopsideshow@oaklandnet.com.

Oakland already has numerous enforcement tools including a decade-old state law, passed for the city’s benefit, that allows police to impound cars for 30 days if they were involved in sideshow activity.

“I want to see cars get towed,” Councilwoman Anne Campbell Washington said. “I want people to understand that if they come here to Oakland to engage in lawlessness that their car will be taken away, and they will not be able to do that any longer. We were able to (stop) this behavior 10 years ago, so I want to get on top of it again.”

The CHP reported towing 10 vehicles involved in the early Sunday morning sideshows.

The impound law, which was passed in 2002, didn’t appear to have much impact on Oakland sideshows. Police records show that sideshows peaked in 2008 with nearly 450 calls for service. However, in 2010, as police, community leaders and some sideshow participants urged an end to the illegal gatherings, the number of calls plummeted to below 50. But sideshows have been on the rise again in recent years, with the freeway increasingly being used as a venue.

The officer-involved shooting occurred about 5:30 p.m. Sunday. Whent did not identify the man shot by police, but said there was no evidence that he was involved in the sideshow activity. The officers, he said, were wearing body cameras, but, in accordance with department policy, had not activated them because they were not actively trying to detain anyone. Internal Affairs and the Alameda County District Attorney’s Office are investigating the shooting.

Contact Matthew Artz at 510-208-6435.