Where's the tip-off?

The Chhattisgarh government provides the state police with ample funds for secret operations, which includes gathering intelligence about the Naxalites. The mystery is that this fund has grown enormously over the years but the expansion does not seem to match the quality of the intelligence, as the assassination of key state Congress leaders last month indicated. When Chhattisgarh was formed in 2000, the state government had allocated Rs 5 lakh for this secret, unaudited fund. That amount has now been increased to Rs 6.5 crore, much of which appears to be spent on informers. So how come the police did not know about Naxalite activity in the Darbha Ghats two days before the attack? The police authorities are unable to explain why the money in the fund is rapidly depleting when the tips in the intelligence box remains empty, too.