Although very few lugged groceries, government food stamp records showed business at Stryker Avenue Market was booming: In one three-month period, the tiny market had more electronic benefit transfer transactions than a nearby Rainbow supermarket more than 28 times its size. The agents thought they knew what was behind it, and their suspicions have resulted in the indictment of Khaffak Sahib Ansari, the market's former owner, on three counts of food-stamp fraud. The indictment, returned Tuesday, alleges Ansari got about $3 million he wasn't entitled to by trading cash for food-stamp benefits for which the government reimbursed him.