Theft from Silicon Valley's hi-tech industry is costing an estimated US$1 million a week, and business and political leaders are pleading for more help from the FBI. A major operation last year has all but stopped the invasion-style robberies often by gangs who raided Silicon Valley computer chip warehouses and manufacturers. But that has not stopped thefts, said Don Brister, head of the San Jose Police Department's hi-tech squad. The gangs are now more likely to track and break into delivery vans, making off with up to $100,000 in chips or computer parts at a time, he said. 'They are well organised - enough to have it pre-planned as to where the break-ins are made and where the product is going to go,' he said.