Purposely lit malicious fires in Imperial Beach in the past week alone have exceeded the number of arson incidents reported in 2011 and 2012, records show.
Flames erupted in four separate incidents in or near IB in the past week, says sheriff's Sgt. Joel Stranger of the Imperial Beach substation.
Molotov cocktails were thrown at vehicles and a sidewalk was set on fire.
A Molotov cocktail is a bottle filled with a flammable fluid with a cloth in the bottle's mouth which is lit to start a fire.
"I definitely don't think we have a serial arsonist on our hands," Stranger said. "They're pretty unrelated."
Around 10:20 a.m. on April 16, firefighters saw the remains of what was a Molotov cocktail outside a motor home parked on the street in the 1200 block of 9th Street.
"The fire guys were actually jogging by and they saw a Molotov cocktail," Stranger said. "There was a motor home next to that and the window was spider-webbed out. It appears to have just hit the window and burned on the street."
Authorities believe the apparent arson occurred between 2 p.m. April 15 and 9 a.m. April 16. No suspects have been identified, he said.
"Molotov cocktails in general are pretty rare. I've only seen a few over my 24-year career, so its weird," he said.
Two days later around 8:30 p.m. a portion of sidewalk near condominiums in the 1000 block of Seacoast Drive was found lit on fire. No damage was reported, Stranger said.
On Sunday around 3:30 a.m. the San Diego Police Department arrested two boys aged 15 and 16 on suspicion of attempting to light a stolen car on fire outside Mar Vista Middle School.
A little over an hour later, around 4:50 a.m. sheriff's deputies were called to 612 7th St., where a Molotov cocktail was thrown at a car. Fire caused "moderate damage" to the back of the vehicle worth an estimated $2,500 but the engine and front of the car were not damaged, Stranger said.
"We don't think they're related," Stranger said of the two juveniles arrested near Mar Vista Middle School and the incident on 7th Street. The sheriff's bomb/arson unit was called in to investigate the fire.
A suspect has been identified but no arrests have been made, Stranger said.
"That's a lot of fire in one week," he said.
No arson incidents were reported in Imperial Beach in all of 2012, according to a recently released crime study compiled by SANDAG. 3 arson incidents were reported in IB in 2011.