Former IAF chief SP Tyagi was questioned by Enforcement Directorate, ED, for the second day yesterday for about eight hours in connection with the 3,600 crore rupees AgustaWestland chopper deal. <br/><br/>Officials sources said in New Delhi that Tyagi was subjected to the marathon questioning after a similar ten-hour session on Thursday by ED investigators. <br/><br/>Sources said Tyagi arrived at the zonal office of the agency and left after about eight hours as he was put through more questions and evidences collected in the case by the Investigating<br/><br/>Officer of the case. The retired Air Chief Marshal was questioned in the same case by CBI for three days this week but this is for the first time he was summoned by the ED.