New Delhi, May 23: Dentist Rajesh Talwar was arrested today on the charge of slitting the throat of his teenage daughter Aarushi, sending shock waves in a country inured to crime and raising questions rarely discussed in public.

The high-profile dentist has also been accused of killing domestic help Hemraj on May 15 night. The 15-year-old girl was killed the same night at the dentist’s Noida flat.

Officially, the police said the motive was to prevent the girl from revealing Rajesh’s “affair” with colleague Anita Durrani.

But a senior officer told The Telegraph Aarushi was killed to stop her from exposing sleaze involving several people. He said many influential people in Delhi — Rajesh is known to have had VIP patients — had a role in the sordid goings-on and there would be pressure from them not to expose the racket.

Rajesh and Nupur, both dentists, owned a clinic at Sector 27 that had two other dentists on its payroll: Anita and her husband Praful Durrani. Rajesh and Anita would be in office from 9am to noon and Nupur and Praful between 5pm and 7pm. Even the pairs’ days off matched.

The source said the Talwars and the Durranis would meet every now and then at the flat and Aarushi would be locked up in her room during such “parties”.

On the day of the murders, Rajesh and Anita had skipped work, both at the clinic and at Fortis Hospital where they were colleagues. The Talwars allegedly exchanged several phone calls with the Durranis before and after the murders.

The Durranis have been detained for questioning and police sources said Nupur was likely to be arrested soon.

The police had found Aarushi’s body in her bedroom on May 16 morning but overlooked Hemraj’s on the terrace and, seeing him missing, declared him the chief suspect. They had egg on their face the next day when a neighbour — a former deputy commissioner of police — followed the bloodstains on the staircase and discovered the body.

At today’s news conference, a cagey Gurudarshan Singh, inspector-general of police (Meerut zone), named Rajesh as the killer but mentioned only the relationship with Anita as motive. He was silent on any role by Nupur, but sleuths unofficially confirmed that she was present when Rajesh slit Aarushi’s throat — and there was a third person, too, whom they wouldn’t name.

Singh went on to add an “honour killing” angle, saying Rajesh was angry with his daughter for having an affair with Hemraj, 45, but provided no proof. In Lucknow, additional director-general of police Brij Lal echoed Singh, saying Rajesh would bring Anita home when Nupur was not present, angering Aarushi. He didn’t mention “the parties”, either.

The police’s eagerness to confine the case to the “affair” has raised questions because there was no visible sign of hostility between Rajesh’s wife Nupur and Anita after Aarushi’s murder when the two women were often seen together. Anita accompanied the Talwars to a temple to pray for Aarushi’s soul and took part in the girl’s last rites.

The senior police source suggested that Aarushi had begun blackmailing her parents, and an expensive camera that had arrived by courier on the day of the murder was payment for her silence. But Aarushi had apparently confided in a friend and Hemraj.

The parents somehow found out, the source said, and Rajesh may have been under pressure from within his VIP swinging set to do something.

IGP Singh’s official version had a gaping hole. He said Rajesh returned home at 11pm and found Hemraj and Aarushi in an “objectionable scene”. In a fit of anger that had been building up because of the girl’s attitude towards his affair, he killed both.

He first murdered the servant on the terrace and, after a swig of whisky, killed his daughter. But if Hemraj was killed on the terrace, what explains the bloodstains on the staircase? The IGP didn’t explain.

Singh also made a slip. Moments after saying “Hemraj was killed first, on the terrace”, he claimed the servant was silenced because he was a witness to the girl’s murder.

Officers said Rajesh was arrested after the police tapped a phone call he made to his lawyer. The dentist claimed he was innocent and had been framed by one “Dinesh Verma”. Police sources could not say who Verma might be.