Ventura police said they have been finding the bicycle chop shops in the dry Ventura and Santa Clara river bottoms.
That means bicycle thieves are taking bikes apart and creating news one to avoid detection.
Police are urging bicycle owners to lock them up and to register them on the city of Ventura's website.
Justin Dreyfuss, the owner of Coastal Postal, said his bike was stolen in front of his business. He said the bike was not expensive.
Dreyfuss said the early inmate release program due to the California's prison realignment plan may have something to do with what appears to be a spike in thefts.