New DelhiPolice on Monday said CCTV footage from the apartment complex helped them unravel the mystery behind the deaths of the elderly couple in a south Delhi’s East of Kailash home.Police said the couple’s masseuse used to visit them twice a week — Tuesdays and Fridays.On January 18, CCTV footage recorded her arriving at the apartment complex at around 11 am, said police.“We also found that her son had followed her to the apartment. While the woman was seen exiting at around noon, none of the cameras captured her son leaving,” said Chinmoy Biswal, deputy commissioner of police (southeast). “We scanned the footage of January 19 in which the teenager is seen leaving the apartment on January 19, almost 24 hours after his arrival, with a trolley bag and wearing a black cap belonging to Virender.”After January 18, there were no CCTV footage of the masseuse returning to the complex, said police.Initially, however, very few clues pointed to murder. The way the bodies were found with over a dozen naphthalene balls and no sign of break-in suggested that the couple may have committed suicide by consuming the pesticide.However, while the flat’s iron and wooden doors’ interlocks were found locked, the wooden safety latch was not in its lock position. Police said the questioning of the couple’s other domestic helps — a cook and a cleaner, also on part-time basis — revealed that the couple had two sets of keys to the flat.“While one set of keys was found in the house, the other was missing,” said an investigator on condition of anonymity. “Their phones too were also missing. This prompted us to probe whether somebody had used the spare keys to enter and murder them.”Police said they suspected the part-time masseuse and her son after they found discrepancies in their statements. They said the woman could not give them a satisfactory answer to why she stopped coming for work in the apartment after January 18. She also allegedly lied about her son following her to the apartment on that day. But when confronted with CCTV footage and other evidence, she confessed, said the police.Another police officer, associated with the probe, said that the juvenile initially tried to mislead them by claiming that he committed the crime with his three friends. He gave the names and addresses of the three men.“We conducted raids in Delhi and Faridabad but could not find them. When we questioned the teenager again, he cooked up another story. An important breakthrough in the case came when found that the couple’s missing cell phones switched on for some time and their last location was in Sangam Vihar, where the juvenile lived with his family,” said the officer.Police said that the masseuse worked for the couple for the last seven years, apart from other families.