Both India and Pakistan then began lobbying for his release into their custody, but India clinched the arrest by providing DNA samples from Ansari's Indian family members, who live in Maharashtra, where Mumbai is located, the officials said.
Intelligence agents are now interrogating Ansari in a secret location on the outskirts of New Delhi.
Ansari told Indian investigators he had gone to Saudi Arabia on Lashkar's orders to raise funds and recruit more Indians as militants. Investigators say Lashkar and Islamic militant groups routinely try to recruit Indians from among the two million Indians living in Saudi Arabia or the millions who visit the country to perform the Haj.
He might have remained in the shadows had he not opened a Facebook account in his real name to find new recruits, the officials said. The Times of India reported last week that Ansari also used the account to contact Lashkar accomplices, who may have been under global scrutiny by intelligence agencies.
Indian investigators followed his electronic trail to Riyadh, and this week used voice recognition tests to match Ansari's voice with the man on the tape. While the Hindi he spoke is similar enough to Urdu that speakers understand each other, there are many words that differ.
Image: Inset shows a picture of Abu Jindal as the background shows the Taj hotel burning under attack.