Bhubaneswar, June 1: Police are yet to unearth the mystery behind the death of 62-year-old social worker Nalini Prabha Das, whose body was recovered from her residence at Forest Park on May 24.

Though the post-mortem report suggested that the woman had most likely committed suicide, the police remained clueless about how the body was found from her residence while the door was locked from outside.

The police said the post-mortem report revealed presence of mark on her neck.

"In case of strangulation, the entire neck portion should have distinctive marks. But in this case, the marks were found on her necks in patches - which suggests that she might have committed suicide," said a senior police official.

However, the police failed to solve the suicide theory as the body was found lying on her bed.

"If she has committed suicide, how come the body found in her room. Besides, the room was locked from outside," said another police official investigating the matter.

The police are yet to find out the circumstances under which the cell phone of the deceased had remained switched off since May 14.

"Though her cell phone had remained switched off since May 14, her neighbours saw her till May 19. So, further investigation is on to find out the truth behind this," said the official.

Earlier, the police were suspecting involvement of the autorickshaw driver, who used to pick and drop the social worker at her residence.

The driver had dropped her home for the last time on May 15.

Ever since the woman's death, the auto driver's mobile phone was in switched off mode. This had raised suspicion about his involvement in the incident.

The police have also nabbed the driver and quizzed him.

But later, the cops gave him clean chit due to lack of evidence against him.

The police have also interrogated a few relatives of the deceased to ascertain the property angle behind the incident, but that, too, failed to provide any conclusive evidence.

"We would analyse the autopsy report again to find out the exact cause of death. The investigation into the case in going on," said deputy commissioner of police Satyabrata Bhoi.