Police have a theory about mysterious Fresno serial bombings
Photo Courtesyof the Fresno Police Department.

Five suspects arrested after a series of seven bombings in Fresno, California, may be linked to white supremacy, law enforcement officials warned at a press conference.

Local police and FBI investigators are probing possible ties to extremist groups after Nazi flags, banners, hats and coffee mugs were found during raids of locations linked to the suspects, according to officials.

Police also recovered 11 illegal firearms, hundreds of rounds of ammunition, methamphetamine packaged for sale and $50,000 in cash.

The motive for the bombings remains unclear.

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"A lot of the pieces of evidence are still being processed. At this point, we cannot say that the motivation was a hate crime or whether the victims were targeted because of their race," Fresno Police Chief Paco Balderrama said at the press conference Wednesday.

"We can't say that for certain," he added. "We haven't solidified the connections to a white supremacist group. But is that a possibility? Yes, it is."

Suspect Scott Anderson, 44, who investigators believe may be the ringleader of the operation, was arrested last week.

He and the other four suspects arrested have been charged with a number of crimes, including possession of bomb-making materials, illegal possession of firearms, and the distribution of methamphetamine.

No one was injured in the series of explosions in the city from December 23 to February 21 that targeted vehicles and one mailbox. A pipe bomb destroyed a vehicle of the Fresno County probation department.

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But Balderrama said there was evidence in the raids that the suspects may have been preparing for larger blasts.

"We found several materials that led us to believe that they were looking to enhance their own skills," said Balderrama. "You start with something basic and then and then you grow, and then make it bigger. That was our concern. It became apparent very quickly that the suspect, or suspects, in this case, were progressing in [their] skill level of making bombs, and also their frequency."

Check out the press conference below or at this link.

Live Fresno Police Press Conference Regarding A Serial Bomb Suspect www.youtube.com