Noah Berger / Bloomberg / Getty Images A farmer stands among walnut trees on his Linden, California, U.S., farm on Wednesday, Sept. Rich Paloma, a former policeman turned reporter, doubts that the string of nut heists in California's Central Valley are isolated incidents. If anything, they're the work of a "nut mafia," he said in an interview with NPR. If so, the shadowy network hit the jackpot with its latest heist: Three trailers loaded with $400,000 worth of walnuts. The thieves cut a hole through a local orchard's fence, hitched the trailers to a getaway vehicle (Paloma suspects it was a tractor) and vanished down a California highway. According to NPR, the heists coincide with a huge jump in the price of walnuts from 60 cents to $2 a pound. With the value of walnut stockpiles tripling in price, the nut mafia may not be such a nutty idea after all.