The Secret Service analyzed 173 mass casualty attacks. Here's what they found.
The 72-page report tallied red flags leading to public attacks between 2016 and 2020.
Watch CBS News
The 72-page report tallied red flags leading to public attacks between 2016 and 2020.
The 66-year-old gunman who went on a killing spree in Half Moon Bay had legally purchased his firearm, had no prior contact with local law enforcement and was an employee of one of the farms he targeted.
Bouquets of flowers were laid in front of a sign that read, "As a community we grieve." It's the same message echoed by Half Moon Bay residents walking down Main Street on Tuesday, a day after the largest mass shooting in San Mateo County history.
The suspect went to a second dance studio after the shooting, but someone there managed to disarm him, the Los Angeles County sheriff said.
California is reeling from a series of gun violence that has claimed 19 lives since Saturday at a ballroom, two farms, and a gas station.
Authorities in Half Moon Bay confirmed seven people were killed and one was critically wounded in a mass shooting Monday afternoon, and a suspect is in custody after turning himself in.
Authorities in Half Moon Bay confirmed seven people were killed and one was critically wounded in a mass shooting Monday afternoon, and a suspect is in custody after turning himself in.
A mass shooting at a gas station in Oakland Monday evening killed at least one person and injured at least seven others, the second mass shooting in the Bay Area Monday and the third in California in three days.
"At the hospital meeting with victims of a mass shooting when I get pulled away to be briefed about another shooting. This time in Half Moon Bay. Tragedy upon tragedy," Newsom tweeted.
As investigators work to determine what motivated a gunman to open fire in a dance hall, residents in Monterey Park struggle to cope with the mass shooting that left 10 people dead.
Mayor London Breed on Sunday pledged that San Francisco police would increase their presence at Lunar New Year events "to ensure safe celebrations" in the wake of the mass shooting in Monterey Park.
The Sunday morning shooting in Southern California has Californians up and down the state on edge.
The gunman was killed after exchanging gunfire with officers, police said.
The gunman was killed after exchanging gunfire with officers, police said.
In times of trauma, a community comes together. That's what Stockton has shown time and again. On Tuesday, they stood united in song remembering a painful day that many shared together more than three decades ago.
Authorities said the home where the shooting occurred was known to law enforcement for gang activity.
A shooter stood over a 16-year-old mother clutching her 10-month-old baby and pumped bullets into their heads in a brazen attack in a central California farming community that left six dead at a home linked to drugs and guns, a sheriff said Tuesday.
Jessica Wilczewski says supervisor who attacked colleagues in a breakroom "made sure who he wanted dead, was dead."
Sacramento's LGBTQ+ community hosted a candlelight vigil Wednesday night in midtown to stop and remember the five lives lost when a gunman opened fire on a gay nightclub in Colorado Springs on Nov. 19.
Fierro said that his military training and the instinct to protect those around him made him react instantly.
The suspected gunman who opened fire at an LGBTQIA+ nightclub in Colorado, killing five and injuring several others, is the grandson of a California assemblymember.
John Suthers says the shooting that left at least five dead "could have been exponentially more tragic" without that intervention in the gay nightclub in his city.
When voters approved Prop. 57, CDCR said inmates would earn early release credits for rehabilitation, good behavior, and education milestones, and would lose credits for bad behavior. But critics argue that's not the case anymore and there's little transparency - pointing to Sacramento mass shooting suspect, Smiley Martin, as a prime example.
The mass shooting prompted a newly minted position, nightlife economy manager, a role Tina Lee-Vogt filled this past Monday.
e police department that serves the Uvalde, Texas, school district has been suspended, officials said Friday, more than four months after a mass shooting claimed the lives of 19 students and two teachers. The decision was made amid several ongoing investigations into the department and its response to the deadly May 24 rampage at Robb Elementary.
The plan includes a $930,568,525 estimate for three phases over a 15-year period.
Citywide camera surveillance has been put in the spotlight due to concerns by some California cities over access that ICE may have to the data collected.
The bipartisan effort aims to place harsher penalties on first-time offenders and to close a loophole that allowed drunk drivers in deadly crashes to avoid jail time.
A California congressman is calling for more railroad oversight. It comes on the three-year anniversary of one of the nation's most destructive railway accidents and just a day after a derailment in Stockton.
A hit-and-run investigation is underway in Elk Grove after a 61-year-old man was struck and killed while fixing a flat tire, police said.
The Super Bowl LX countdown has the NFL trying to tackle concerns over U.S. Immigration and Customs Enforcement activity around Levi's Stadium.
A year after CBS News California Investigates exposed secrecy inside the California FAIR Plan, the insurance commissioner is backing a bill that would open meetings and financial records and require public reporting for the state's insurer of last resort.
The plan includes a $930,568,525 estimate for three phases over a 15-year period.
A Stockton mother remains missing as family, friends, and community members have been searching for her in Merced County since last week.
Citywide camera surveillance has been put in the spotlight due to concerns by some California cities over access that ICE may have to the data collected.
Adoption is becoming the newest way to assist people who are homeless in Sacramento. Here is an inside look at the unusual fundraising effort at one local homeless shelter and how the money will help.
Mark Zuckerberg and his company, Meta, are putting $50 million into a partnership to build a new Sacramento State University campus where old, unused state office space currently sits downtown.
The Sacramento Police Department said officers shot and killed a suspect while responding to a bank robbery on Thursday afternoon.
It has been a year and a half since Athena and Mateo Lee were last seen after their mother, Angelica Bravo, was found dead in a north Sacramento home.
Troubled by tariffs, some Sacramento Valley farmers and ranchers say their profits are plummeting due to new federal trade policies.
The Super Bowl LX countdown has the NFL trying to tackle concerns over U.S. Immigration and Customs Enforcement activity around Levi's Stadium.
A 59-vehicle pile-up shut down a main California highway Saturday morning as fog severely limited visibility.
A California Supreme Court ruling involving a Sacramento traffic stop bars police from stopping or ticketing drivers over loose marijuana, ruling that it's similar to spilled beer and not readily consumable.
California's snowpack saw a drop in January after several weeks of no snow eliminated gains from a series of atmospheric rivers weeks ago, water officials said on Friday.
The Fremont factory will still manufacture Model 3 and Y, but the space where Model S and X are made will instead focus on mass production of Tesla's Gen 3 Optimus robots.
The Super Bowl LX countdown has the NFL trying to tackle concerns over U.S. Immigration and Customs Enforcement activity around Levi's Stadium.
Giveaways, fireworks nights and themed days celebrating the team's temporary home highlight this year's promotional schedule for the Athletics.
Erin Jackson is the first Black woman to win an individual gold medal at a Winter Olympics. Frank Del Duca is the first bobsledder in 70 years to carry the U.S. flag.
Rookie Will Riley scored a season-high 18 points, including a go-ahead 3-pointer with 2:07 left, and the Washington Wizards beat the Sacramento Kings 116-112 in a matchup of last-place teams.
The San Francisco 49ers are hiring former Atlanta Falcons head coach Raheem Morris as their new defensive coordinator in hopes of finding a long-term solution to a revolving door at the spot.
The Super Bowl LX countdown has the NFL trying to tackle concerns over U.S. Immigration and Customs Enforcement activity around Levi's Stadium.
Starting March 1, the SBA will no longer guarantee loans for small businesses owned by foreign nationals, including green card holders.
Hillary Clinton will appear for a deposition on Feb. 26, while former President Bill Clinton will appear on Feb. 27, according to the House Oversight Committee.
The Clintons made a last-ditch effort to avoid a contempt vote.
A slew of notable individuals appear in the latest Justice Department release of Jeffrey Epstein files.
Health officials in the East Bay said a man has died from consuming toxic wild mushrooms, amid an ongoing spike in mushroom-related poisonings throughout California.
Health officials in Napa County confirmed Wednesday that a child has been diagnosed with measles in the county's first case in nearly 15 years.
The Harmony Health Street Medicine team spends their days visiting encampments and connecting with vulnerable people, meeting them where they are and offering care outside of a clinic and without barriers.
Kaiser Permanente has reached a lawsuit settlement over alleged patient data breaches involving Kaiser websites and mobile applications, with members eligible to receive a payment from a $46 million settlement fund, the health care giant announced.
After the ACA tax credit lapsed in December, enrollees are opting for less robust health plans or dropping coverage altogether.
Finding the perfect dress isn't easy, but now, selling them could become a lot more challenging.
This weekend, Placer County is hosting its annual Sip Into Spring event, offering free or discounted tastings at more than 20 wineries along what's known as the Placer Wine Trail.
From fruits and veggies to car parts, economists project that businesses will pass along the cost of the tariffs to customers.
An economic blackout was underway Friday as activists nationwide encouraged people not to spend their money at large corporations, retailers and fast-food chains for 24 hours.
San Joaquin County's retail theft reporting app has only been around for six months and is already bringing a sense of calmness to local business owners.
President Trump and Gov. Gavin Newsom have made several different claims about California gas prices. Here's what we found.
This year-long investigation provides an unprecedented look at California's one-party supermajority legislature through the eyes of grieving parents who discover how California lawmakers kill popular bills by not voting.
This year-long investigation by CBS News California investigative correspondent Julie Watts examines the many components of California's new tougher-on-crime law.
A Natomas mother demanded that her daughter be exhumed and cremated after a Sacramento cemetery moved her grave without telling the family.
The California Highway Patrol captain accused of workers' compensation fraud was the commander in charge of the fatal Mahaney Park shootout in Roseville, three officers who worked under him at the time of the shootout said.
CBS13 and the Call Kurtis consumer investigative team devised an idea on how to lower what consumers owe on their credit cards -- and it begins with a simple phone call.
No one wants to think about death. However, it's important to plan on what happens to your digital assets after you die.
After spending $18,000 on waterproof laminate floors, a Natomas couple spotted damage after the first cleaning.
More than a year after Hai Pham canceled the trial membership, he kept getting charged every month for it.
A Natomas mother demanded that her daughter be exhumed and cremated after a Sacramento cemetery moved her grave without telling the family.
A major home developer is rethinking how communities are built in wildfire-prone areas and the future is taking shape in El Dorado County.
San Joaquin County secured a grant aimed at helping to build a wildfire protection plan for the entire county.
More than two dozen structures were destroyed in a wildfire in the eastern Sierra Nevada mountains on Wednesday afternoon, officials said.
Clean-up has started in Chinese Camp after the TCU September Lightning Complex Fire ripped through the Gold Rush town earlier this month.
The fires burning in Calaveras and Tuolumne County caused air quality officials to issue a smoke advisory, warning people that the air quality may be unhealthy for sensitive groups.
A Sacramento County dog picked up thousands of miles from home after he went missing five years ago was reunited with his family on Wednesday.
What started as a suspicious circumstances call for Rancho Cordova police ended with a newborn surprise.
A once-empty lot behind Church of the Cross in north Modesto now hosts a thriving community garden with more than 140 plots and growers from across the globe.
A Sacramento-area middle school history and English teacher is in the running to win big as America's Favorite Teacher, a title her students think she is more than worthy of being awarded.
Junior Romello Bruhn of Woodland Christian High School is closer than ever to scoring 3,000 career points, something only 13 high school athletes have accomplished in California state history.
A hit-and-run investigation is underway in Elk Grove after a 61-year-old man was struck and killed while fixing a flat tire, police said.
Charlie Lapastora reports.
Here is the full February 2026 episode of What's in Season with Michael Marks.
Ashley Sharp reports.
A California congressman is calling for more railroad oversight. It comes on the three-year anniversary of one of the nation's most destructive railway accidents and just a day after a derailment in Stockton.