The police said it did not take them time to arrive at the conclusion that the victim, Sarla Patel, had been killed by somebody she knew and did not feel threatened by.
"The scene bore telltale trail of the killers," said Himanshu Roy, joint commissioner of police (crime).
To begin with, investigators did not find signs of violence or force inside the house or near the flat door. "It did not take us time to realise that the killers were well-known to the victim. After seeing two empty glasses on the teapoy, our suspicion strengthened. This is in the backdrop of the fact that normally senior citizens, especially women, are careful and don't allow anyone inside the house when they are alone," Roy said.
Soon, the police also realised that the killer/s had to be aware of the fact that Patel would be alone at home when they struck.
Crime branch detectives began shortlisting probable suspects by questioning the watchmen and neighbours and checking the movements of those known to the victim in the hours preceding the murder.
They realised they were closing in when one of the watchmen revealed that he had got a few calls from Patel's grandson in the afternoon, asking whether his father and grandfather had left home. The boy's mother too told the police that she had received a call from him, inquiring her whereabouts.
"Our conviction became strong. Following brief questioning, the boy broke down and confessed to the crime," Roy said.