San Diego police are searching for a man suspected of starting a fire inside a downtown apartment building early Tuesday morning.

Around 2 a.m., SDPD officers and San Diego Fire-Rescue Department crews were dispatched to the building located at 1453 Fourth Ave. after a woman reported that a man was setting things on fire inside the building.

The fire set off alarms, forcing tenants to evacuate the building. One man was hospitalized for smoke inhalation.

The building’s sprinkler system extinguished the fire, and responding firefighters helped prevent most of the water damage caused by the sprinklers.

Officers forced their way into the apartment where the fire started, but the suspect was not inside. Police questioned the woman who called 911 to report the incident; her relationship to the suspect was unclear.