Last month cops busted a Columbia employee, George Castro, after he allegedly siphoned $4+ million of the university's cash into a private bank account. Though Castro pled not guilty yesterday, that doesn't mean the police stopped looking for the missing loot. And they didn't have to look far. Less than two days after Castro's arrest the Manhattan DA's Cybercrime and Major Economic Crime bureaus say they had not only identified the banks where the crook was keeping his cash, but were able to seize and freeze a good $4 million of it. "We got to him quickly before the money could be dissipated," Manhattan DA Cyrus Vance told the Post.