The California state senator behind a law to restrict vaccine exemptions was attacked on the street Wednesday by an anti-vaccine activist, police say. Anti-vaxxer Kenneth Austin Bennett livestreamed the entire incident on Facebook and can be seen shoving state Sen. Richard Pan from behind before saying into the camera, “I probably shouldn’t have done that.” In the moments leading up to the physical confrontation, Bennett appeared to run into Pan on the street before blasting him for saying vaccines are safe. The Sacramento Police Department later confirmed that Bennett was cited for assault over the incident, and Bennett himself admitted that he had “pushed” Pan on Facebook, claiming that he’d done so for the state senator’s “lying” and “laughing at us and for treason.” He went on to say in the video that Pan “would be hanged for treason, for assaulting children, for misrepresenting the truth” if he got what he deserved.

Shannan Velayas, Pan’s spokeswoman, said the state lawmaker has faced an increase in threats from anti-vax activists since he authored a bill tightening vaccine laws and school immunization requirements. “This is moving from a peculiar fringe curiosity to a violent extremist movement,” Velayas was quoted as saying by the Los Angeles Times.