A US national was detained at the Indira Gandhi International airport in New Delhi last night after a knife blade was found in his hand baggage during the security check while he was leaving for Doha.<br/><br/>The CISF personnel who detained the US national, identified as Winston Marshal Carmichael was later handed over to Foreigner regional registration office. He was to leave for Doha in a Qatar Airways flight. Carmichael, who has a tourist visa to India, Pakistan and Bangladesh, came to India from Pakistan.<br/><br/>He had visited Pakistan and Bangladesh on earlier occasions also. Delhi Police Special Cell and IB is questioning him.<br/>