WALNUT CREEK (CBS SF) — A small explosion possibly linked to the use of illegal fireworks rocked downtown Walnut Creek late Monday night, shattering a window in a commercial building.

Local residents called 911 around 10 p.m. reporting the blast to police. Arriving officers discovered the remnants of what appears to be a large firework set off in a metal pipe and several windows shattered in a building at 1200 Mt. Diablo Blvd near Mt. Pisgah.

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Walnut Creek resident Ben Seeley lives nearby and didn’t just hear the explosion, he felt it.

“Kind of shook the house a little bit and then it was over. It wasn’t too big or anything, but just a nice shake,” explained Seeley. “I was just watching TV with my wife. Our patio door was open and all of sudden this huge ‘BOOM!'”

Walnut Creek police immediately began searching the surrounding area for a possible suspect.

While little other information was released by authorities as of early Tuesday, video shot at the scene showed boxes of illegal fireworks stacked on a police vehicle and a man detained in the rear of a police car.

Investigators later confirmed they arrested 32-year old Shayne Guerrero on several charges including possession of illegal fireworks, child endangerment and vandalism.

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When asked if he immediately thought the explosion was from fireworks, Seeley replied, “That was my guess. July 4th is coming up and I was like, ‘It’s probably fireworks.’ I was a little hesitant to explore further, but fireworks were my first thought.”

Fireworks are illegal in Contra Costa County with local authorities warning residents about the dangers they pose in the bone-dry hillsides.

Last week, fire authorities in Contra Costa County showed off some of the thousands of dollars worth of illegal fireworks confiscated during East Bay undercover operations in the past month.

Fire investigators have been conducting undercover purchases of illegal fireworks in an attempt to reduce the quantity of dangerous explosives available on the street.

Most of the charges so far have been in connection with the possession, selling or delivering of fireworks. Any use of fireworks of any type is illegal in Contra Costa County and downright dangerous during the extreme drought conditions gripping the Bay Area and California.

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So far, they have arrested four people this month in connection with fireworks. One of the people taken into custody was the suspect accused of sparking the May 31st Antioch fire that destroyed eight apartment units.