An 18-year-old student was killed and three other people, including an 11-year-old child, were wounded in a shooting Wednesday evening during a high school graduation event in Northern California, police said.The shooting occurred during a Sem Yeto High School graduation ceremony held at Fairfield High School, according to authorities.Fairfield Police Officer Michelle Belyea said three victims who suffered gunshot wounds were ages 11, 20 and 25. The 18-year-old student later died from injuries sustained during the incident.The surviving victims were receiving medical treatment, Belyea said.SHOOTING REPORTED AT WILMER-HUTCHINS HIGH SCHOOL IN DALLAS"We don't have any information that there's any ongoing threat to the community at this time," Belyea told reporters. "This is still a very active incident."Police have not released information about a suspect and said additional updates are expected later Thursday.Sem Yeto High School is a continuation school within the Fairfield-Suisun Unified School District.SHOOTING AT ANTIOCH HIGH SCHOOL IN TENNESSEE LEAVES 3 INJURED, PROMPTS LOCKDOWNWitnesses described a chaotic scene as families gathered following the ceremony.One witness told KTVU that he was near an area where graduates were taking photos when a man ran up and began shooting. The witness said people immediately scattered as panic spread through the crowd.Another witness told the station she heard several gunshots before family members urged her to run.MASS SHOOTING AT STOCKTON, CALIFORNIA, BANQUET HALL LEAVES 4 DEAD, 10 WOUNDEDFairfield Mayor Catherine Moy said residents should rely on information released by the Fairfield Police Department as investigators continue working the case."My heart is breaking for the students and families involved," Moy said in a statement. "I graduated from Fairfield High School and I can't get my head and heart around this tragedy. I'm shaken to my soul."Suisun City Mayor Alma Hernandez also offered condolences, saying the tragedy would leave a lasting impact on students, families and the broader Fairfield-Suisun Unified School District community.The investigation remains ongoing.