The police have, however, found the box of sweets, which `Mr Sharma' had reportedly brought along with the invitation card. Shivani's husband Rakesh Bhatnagar has said that Shivani had called him up at around 3.30 pm yesterday to say that `Mr Sharma' had come with a box of sweets and the invitation card.

Bhatnagar said that when he spoke to `Mr Sharma', the latter told him that he had been sent by Mr Adhikari, a journalist working in a local daily in Chandigarh. Rakesh said that he did not know anyone called Adhikari.

The police have, meanwhile, ascertained that the box of sweets had been bought from a sweet shop in the Preet Vihar area of East Delhi. They have questioned a salesman at the shop, but the latter has not been able toprovide clues about the customer.

The register maintained by security personnel at the main gate of Navkunj Apartments, where Shivani lived, has revealed that three persons had come to visit her between 2 pm and 4 pm -- police suspect she was killed during this period. The police have traced two of her visitors, but the third, who logged in as Rajeev Bhatnagar at 2.50 pm with a Chandigarh address, is missing.

According to a senior official in the Crime Branch of the Delhi police, the address furnished by Rajeev Bhatnagar has been found to be fictitious. Investigators are also trying to establish whether the visitor was feigning his identity.

Among the other visitors to Shivani's house yesterday afternoon was a washerman called Raju and her maid-servant-cum-cook Lakshmi Mangala. While Raju has said he dropped in at around 2 pm, Mangala has told the police that she left Shivani's house before 2 pm. ``So far, we have nothing to establish their involvement,'' said another senior Delhi police official.

Thepreliminary report of the post-mortem on Shivani's body has indicated that she died due to strangulation before she was stabbed. An electric wire, two kitchen knives and the broken handle of a frying pan were found near her body.

Though the preliminary report has not revealed clues to the number of assailants, the police are still exploring the possibility of more than one person's involvement in her murder. ``Two glasses of water were found in the living room; two cups with tea, and some and biscuits and dry fruits in a tray were found in the kitchen. It is unlikely that Shivani would have prepared tea for strangers. Besides, robbery does not seem to have been the motive,'' said the official from the Crime Branch.