Kolkata: For the first time, Kolkata Police implemented 3D mapping system to take pictures of the incident spot at Netaji Nagar elderly couple murder. This would help the investigators to mark objects clearly irrespective of sizes.It will also help the investigators to reconstruct the crime scene. According police, during the probe, several persons were interrogated. Among them there were two promoters who has contacted the deceased Dilip Mukherjee (80) and Swapna Mukherjee (72). Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataInvestigators also found two bank accounts with Rs 1.5 lakh and Rs 80,000 respectively. Police also examined CCTV footage and found that a person is walking aimlessly. Also, it was found that there were 10 almirahs in the house out of which nine were opened using keys. On Wednesday, police broke open the almirah which was left intact and found Rs 2.5 lakh from there. Also some fixed deposits worth approximately Rs 30 lakh were also found. However, investigators are still in the dark about the motive. Also Read – Lightning kills 8, injures 16 in stateIf the murderers had the motive of robbery why they did not opened the last almirah. Also if anyone comes to Mukherjee family’s house then Swapna used to see from first floor and then used to open the door. After knowing this information, the police are almost sure that the murderers are known to Mukherjee family. The police also came to know that a few days ago Mukherjee family had painted the house for which several labourers worked there. Three such labourers were also detained and questioned but nothing suspicious could be traced. Police suspect professional killers are not involved in the case.