An American citizen was detained at the Indira Gandhi International airport in New Delhi after a knife was found in his hand baggage and a FBI team joined Indian investigators to probe if he had any terror link like LeT operative David Headley.
Investigators were also conducting a chemical examination of the herbal plant "Shilajit" in which 61-year-old Winston Marshall Carmichael had allegedly concealed a knife. He remained in detention for the second day today.
The FBI officials were also questioning him and verifying his activities back in the US, official sources said.
Carmichael, a convert from Christianity to Islam, had a tourist visa to India, Pakistan and Bangladesh and came here from Bangladesh. He was detained minutes before he was to board a Qatar-bound flight last night.
He arrived in India in January last week and travelled to Pakistan in Samjauta Express where he had attended religious congregations of Tabliq-e-Islam and went up to Karachi before flying to Dhaka in a Pakistan International Air flight.
Carmichael later entered India through West Bengal and took a train to the national capital where he was staying in a hotel at Nizamuddin.
The knife concealed in a herbal plant 'Shilajit' and recovered by CISF from the hand baggage of Carmichael was 4.3 by 1.5 inches which is too small to be considered in the category of a weapon, the sources said.
The Shilajit plant, as claimed by the detained US national, had been sent for a chemical examination and a report was awaited.
In the meantime, the Delhi Police and security agencies were verifying his places of stay in the national capital and travel from West Bengal.