(KRON) — A San Mateo hospital went into lockdown Tuesday night after a man threw a firework in the direction of the building and threatened to kill a security guard, the San Mateo Police Department said.

SMPD responded to San Mateo Medical Center, located at 222 West 39th Ave., after a 911 caller said she heard a loud “bang” near the hospital. A police investigation revealed a suspect, later identified as Miguel Boch-Chamale, was asked to leave by hospital security after he tried to enter the premises, police said.

When in a parking lot, Boch-Chamale used a knife to threaten a security guard’s life, police said. The suspect ran at the security guard, and the guard fired his gun into the air, per SMPD.

After this, Boch-Chamale ran away and threw what was later determined to be an exploding firework at the security guard.

SMPD officers found Boch-Chamale at about 11:50 p.m. in the area of 36th Avenue and Colegrove Street and arrested him on suspicion of assault with a deadly weapon and criminal threats. SMPD is investigating the incident.