Shariq Usmani, working on a project in the Defence Research and Development Organisation, was picked up from his New Delhi home late Wednesday on suspicion of espionage, they said.

The police said they suspected Usmani of spying for Pakistan when they traced calls from his house to an address in the port city of Karachi three days ago.

Usmani was freed Thursday after he said he had been speaking to one of his uncles.

Like many Indians, Usmani has relatives across the border.

India and Pakistan are currently seeking to mend ties but mutual suspicion remains.

WAR.WIRE