So far, the police say they have established that the four youths had robbed a bus conductor on January 14; three days later they robbed three buses at Vayusena Bad, M.B. Road and near Aurobindo College; a couple of days later on January 20, they had robbed a bus conductor at Vasant Vihar, and an hour later robbed two Mother Diary milk booth attendants at Lakshmibai Nagar.

According to DCP (south) P.K. Srivastava, the breakthrough in the cases followed the arrest of Arun. The police were able to trace him after a bus conductor said he had spotted Arun in the PVR Anupam Complex area.

Arun reportedly confessed to the robberies, and also told the police that Shiva was the mastermind. Yesterday, a police team from Ambedkar Nagar police station intercepted Shiva, Vijay and Sanjay on the Mehrauli-Badarpur Road. The trio were reportedly travelling in a stolen Maruti car. Srivastava says one of the youths fired from a country-made revolver, when the police team intercepted them. The policemen retaliated. No one was, however, injured in the gunfire. The police have recovered a country-made pistol and two knives from them.

Srivastava says both Shiva and Vijay have criminal backgrounds. Shiva also served a five-year-prison term after he was convicted for his involvement in his girlfriend's murder. He was released in 1997.

Vijay, who used to work as a ticket-checker in PVR Anupam cinema, was arrested earlier in connection with a car-theft case. Sanjeev and Arun, however, didn't have any criminal cases against them, when they met Shiva and Vijay.

``Each of the youths used to work in or around the PVR complex. After finishing their day's work around 7 p.m., they would assemble outside a fruit juice shop, drink alcohol, drive to bus stops and milk booths in stolen cars and loot the of occupants of those place,'' says Srivastava.

Shiva, who masterminded the robberies, has reportedly told the police that the group also attack their targets before 10 p.m., when traffic was still heavy on the roads of Delhi. ``He has told us that he picked up all these tricks while serving his sentence in Tihar. Committing crimes during rush-hour traffic would enable him to avoid a police chase. Secondly, he contends that since it is difficult to trace stolen money, unlike other goods, he stuck to looting only cash,'' adds Srivastava.