Police identified the murder suspect Podilappu Suresh Kumar, who was seen waiting at the Avadi railway station at 11.56pm on November 26.
A team then combed CCTV camera footage at Chennai Central station and found a clip of the couple and their three-year-old son walking into the station to buy tickets. On November 27, Jagadeesan, 67, and his partner Vilashini, 61, were found dead at their home in Avadi.
At Central, Kumar’s wife Bhulakshmi, who was carrying a bag, was seen accompanying him with their son. They were last caught on camera boarding the Howrah Express and are believed to have left for their hometown in Andhra Pradesh. Police are also considering the possibility of the couple hiding in some remote village in the neighbouring state.
A team headed by Avadi police inspector Bharathi is working with a team from the Andhra Pradesh police to trace them. Police had earlier released pamphlets, bearing photographs of the suspects, which were circulated to all police stations.
People who have spotted the couple can approach the city police control room or the assistant commissioner of police of Avadi range who is available on 94448-03562 and 94981-06608.
Police have also posted the pamphlets at bus terminals and railway stations.
Preliminary inquiries revealed that Kumar and Bhulakshmi migrated to Avadi and stayed at Kamarajar Nagar. They were later employed at Jagadeesan’s house and were also offered accommodation.
Investigating officers said they couldn’t get much information from Jagadeesan’s relatives. Many said the couple rarely showed up for family functions.