Three hours after they took him around town, generating information and getting closer to the country's most-wanted man with every location that they visited, the Maharashtra Anti-Terrorism Squad (ATS) nabbed their source at the last moment.
For the special team of the Delhi Police, it had seemed like a routine day during the month-long operation to nab Yasin Bhatkal alias Shahrukh on January 8.
"We had spent the entire day with Mohammad Naqi, through whom we could have reached Shahrukh, and visited several locations in Mumbai to gather clues," said an officer.
The special team had reached Mumbai on December 10 and, with Naqi's assistance, was able to identify the flat where Shahrukh, and two Pakistani bombers Waqas and Tabrez, had been staying on rent before the serial blasts there on July 13.
The Delhi Police team was staying at a rented flat just a kilometre away from the trio's former hideout in Habib Building near Palace Cinema in Mumbai's Byculla (east), police said.
In order to not attract attention, Naqi was asked to stay with his brother at his factory not far away in Byculla (west).
"Since we were under cover, we just dropped Naqi somewhere near his brother's factory and went home to avoid any suspicion. Three hours later, the (Mumbai) ATS barged into Naqi's brother's factory and arrested him," the officer said.
Identified as Rafi Ahmed, Naqi's brother was detained and forced to lead the ATS to Naqi who was then kept under custody for three whole days and questioned. Finally, on January 11, he was arrested for using fake documents to procure a SIM card that he was using, police said.
"The next day, we found an ATS team standing guard at Rafi's factory when we went to meet him. As soon as reports of Naqi's arrest surfaced in the local media, the whole operation went bust," the officer added.
The Delhi Police team returned on Tuesday.