Tanzil Ahmad's nephew Amir, based in Saudi Arabia, who had tipped off Delhi Police about Muneer's involvement in the Kamla Nagar robbery.
Muneer, the mastermind behind the murder of NIA officer Tanzil Ahmad, was involved in six criminal cases in the national capital, including the murder of a police official in Jaffrabad and the Rs 1.50 crore robbery in Kamla Nagar in which a security guard was killed, Delhi Police said on Tuesday.
It was Mr Ahmad's nephew Amir, based in Saudi Arabia, who had tipped off Delhi Police about Muneer's involvement in the Kamla Nagar robbery, a case which remained unsolved for more than one and half year, a senior official said.
Amir and Muneer were classmates at a school in UP's Bijnor and it was Amir who had helped Muneer and his friend Ashutosh rent rooms near Mukimpara and Bara Hindu Rao, both located in north Delhi, in 2014.
Police then tracked down Ashutosh who was lodged at a jail in UP in connection with a murder case in which Muneer too was a co-accused. While he was brought to Delhi on transit remand and being interrogated by Delhi Police, the Uttar Pradesh Special Task Force (STF) arrested Muneer from Noida on June 28, the official said.
The evidence which police had gathered after interrogation of Ashutosh were cross-examined with Muneer's confessions, which led police to six separate criminal cases executed by Muneer in Delhi between 2013 and 2015.
The cases include the four gunpoint robberies in southeast Delhi's Jamia Nagar and Sarita Vihar areas, the victims were shot at in two of the cases, the robbery-cum-murder case at Kamla Nagar and the killing of a police official in Jaffrabad.
On September 2014, Muneer and one of his associates allegedly shot dead a 26-year-old constable in Jaffrabad and made away with his service revolver. Two months later, they plotted the Rs 1.50 crore Kamla Nagar ATM loot, the official said.
Muneer and Ashutosh shot dead a security guard and fled with a bag containing Rs 1.50 crore cash, which was meant for refilling ATM machines in Kamla Nagar area, close to Delhi University Campus, on a motorbike.
They dropped the bag in north Delhi's Mukimpura and abandoned the motorbike in Okhla, over 13 km away. Muneer kept the entire loot amount after Ashutosh's arrest, the official added.