A small fire was found burning inside an abandoned Chula Vista building early Thursday, two days after police shut down an illegal marijuana dispensary at the same location.

The fire was reported around 6 a.m. at the building on Broadway near Moss Street. When firefighters arrived they found smoke coming from the roof of the building.

After forcing their way inside, crews had to make their way through a maze of walls erected when the business operated as a dispensary to find the “seat of the fire,” Chula Vista Battalion Chief Darrel Roberts told OnScene TV. He said the building didn’t have a traditional layout.

“It was very compartmentalized,” he said.

Video of the building showed windows with vertical security bars. No one was injured and no one was found inside by firefighters.

Roberts said fighting a fire in a building that isn’t up to code poses additional risks to firefighters.

“Buildings like this are firefighter killers,” he said, explaining that firefighters who might have zero visibility will run into walls in unexpected places. “It puts our firefighters in danger. It creates a new hazard and it is difficult because we have a lot of these in the city.”

The cause of the fire is under investigation but it is considered suspicious in nature.

Police officers on Tuesday served a search warrant at the dispensary, seizing $1 million in cannabis products and $10,000 in cash. Two loaded handguns also were confiscated. No arrests were made but police intend to forward a report to the District Attorney’s Office, which will determine if a criminal case will be filed against the business owners, police Lt. John English said.

Police believe the dispensary was operating for a little more than a year before it was shut down, according to Chula Vista police Lt. Dan Peak.