Nagpur: A crucial CCTV clue they dubbed as the ‘Red cap theory' helped Nagpur Crime Branch and Gittikhadan police identify the key suspect in a blind murder case within 24 hours. The key suspect, a milkman, is yet to be nabbed while another accused has been rounded up. Loan recovery agent Ajay Shriwas (42), was found dead with more than 25 stab wounds in his flat at Gourkhede Complex under Gittikhadan police station limits on Saturday. The suspect entered the house without asking anyone, and was aware of the CCTV placement, which showed he took precautions to hide his identity, said police.The CCTV camera at the spot was non-operational but footages from nearby areas proved decisive. One of the CCTV cameras captured a man wearing a red cap, with his face covered by a scarf and his chin lowered, hurriedly leaving the area on foot and boarding an autorickshaw near a junction close to the crime scene.The footage became the breakthrough lead. The distinctive red cap helped police track the movements of the suspect across multiple CCTV cameras. The ‘Red Cap Theory', as police called it, guided the entire probe.Crime Branch teams scanned footage from several locations, questioned dozens of people, including friends, loanees and acquaintances of the victim. A woman from the Pachpaoli area with whom Ajay had a close relationship, along with her husband, was also questioned. The trail ultimately led to a milkman who is now the prime suspect. Police teams from Crime Branch and Gittikhadan are actively pursuing the suspect.Senior officers said Ajay had no criminal background and there was no immediate motive visible. Ajay's mother passed away just 14 days earlier, and the final rituals were performed on Friday. Police believe the murder happened soon after Ajay returned from a lunch with friends on Saturday. The fact that the victim allowed the killer inside suggests they were acquainted, said police.