Police in Riverside are investigating how an unarmed contract security guard brought a loaded handgun onto Lincoln High School's campus during the annual homecoming dance on Saturday night, a breach of district policy that led to the guard's immediate arrest and suspension.
The weapon was discovered shortly before 9 p.m. when a student reported seeing the guard handle what appeared to be a firearm near the gymnasium entrance, according to two students who attended the dance and spoke with the Riverside Herald. School administrators confronted the guard, identified by police as Marcus Dalton, 34, and secured the weapon before contacting law enforcement. No shots were fired, and no injuries were reported.
Riverside Unified School District Superintendent Elena Voss said in a statement Sunday that the district was "deeply troubled" by the discovery and had terminated its contract with Sentinel Security Services, the private firm that employed Dalton. "While we are grateful that no one was harmed, this represents a serious violation of our explicit policies and the trust our community places in us," Voss said. The district prohibits all firearms on campus during student events, including those carried by contracted security personnel.
Riverside Police Department spokesperson Officer Daniel Reeves confirmed that Dalton was arrested at 9:47 p.m. on suspicion of carrying a concealed weapon on school grounds, a felony under California law. Dalton was booked into the Riverside County Jail and released Sunday morning on $25,000 bail. He has been suspended from all assignments with Sentinel Security pending the outcome of the investigation, a company representative said Monday.
Police have not determined whether Dalton brought the gun intentionally or forgot it was on his person. Investigators are reviewing witness statements and security footage from the event to establish a timeline of his actions after arriving for his 6 p.m. shift, Reeves said. Dalton could not be reached for comment.
The case has intensified scrutiny of how Riverside Unified vets and oversees private security at its 12 campuses. District records show that Sentinel Security has provided unarmed event staff to Lincoln High since 2019. State law generally bars concealed carry on K-12 school grounds, though limited exceptions exist for licensed security guards with district authorization—which Lincoln High's dance policy does not permit.
Parents and students said they were alarmed that a weapon went undetected for roughly three hours at a crowded student event. "We're told these dances are safe, that everything is checked," said Maria Santos, whose 16-year-old daughter attended the dance. "Then we find out the person supposed to protect them was the threat."
The district has scheduled a community safety meeting for Thursday evening and said it will conduct an independent review of its event security protocols. Police expect to forward their findings to the Riverside County District Attorney's Office within two weeks.
