Mumbai 26/11 Handler Nabbed, Courtesy Saudi Arabia

A much-wanted terrorist who was among the six instructors or handlers of the men who attacked Mumbai on 26/11 was arrested by the Delhi police on June 21, 2012. One hundred and sixty-six people died in that attack in 2008.

Sayed Zabiuddin Ansari, alias Abu Hamza, was taken into custody by the Delhi police. He was deported from Saudi Arabia — where he had been living under an assumed identity — and handed to Delhi Police after landing at New Delhi's IGI airport on June 21, 2012; sources said India had worked closely with Saudi Arabian intelligence officials to track him down. (Wikipedia; India Today, July 2012)

Ansari, allegedly a member of Lashkar-e-Taiba (LeT), which carried out the Mumbai attacks, was a key figure in the investigation: intercepts from the attacks had captured a handler coaching the attackers in fluent Hindi, and investigators said Ansari was that voice — evidence that the attackers were being directed in real time from Pakistan.

His arrest was significant not just as a capture but as a corroboration. For years, Pakistan had denied any link between the attackers and Pakistani soil. A handler in Indian custody, telling his own story, was harder to dismiss.