A Yemeni origin al Qaeda "lynchpin", recently arrested in Pakistan, had been living in the country for almost 10 years and is said to be an expert in computers and explosives.
Al Qaeda operative Mohammed Ali Qasim, alias Abu Sohaib al Makki's arrest, yielded a "treasure trove" of information, the Dawn newspaper said in a report.
The report said it's not clear when Makki, 34, started living in Karachi with his family. The exact date of arrest is being kept secret because security agencies are working to unearth his "elaborate terror network" in the city.
It has been claimed that Makki was arrested days after Osama bin Laden was killed in Abbotabad. While others said he had been under surveillance since the beginning of this month, but was arrested on Tuesday.
Before moving to Karachi, the terrorist of Yemeni origin lived in South Waziristan, North Waziristan, Peshawar and Faisalabad. The daily said Makki had been in Pakistan since June 2001.
He was taken into custody along with his wife and three children.
Initial investigations said that he had earlier operated along the Pak-Afghan border facilitating movements of al Qaeda operatives, but later started targeting Pakistan and got involved in terrorist activities in Karachi, including bombings and probably target killings.
Although, security officials dismissed as speculative, reports that he was acting as a courier between bin Laden and Ayman Zawahiri, they admitted that he had been in touch with al Qaeda's top leadership and one of the sources described him as a lynchpin for the terror organisation.