Exactly a week after the girl's murder came to light, Meerut Zone Inspector General Gurdarshan Singh told a press conference that Talwar was arrested after enough evidence was gathered, including the "strenuous cover-up" attempts by the dentist.

He said Talwar first killed the domestic help on the terrace of the house in the small hours of May 16 and then came down to kill his daughter after having some whiskey.

Singh said investigations were on and parried all questions whether any more arrests have been made in the case.

There have been reports that Nupur, wife of Talwar, also a dentist, and his doctor colleague Anita Durrani have been

detained in connection with the twin murder.

"Investigations are on and we have revealed to you details about which the probe is over. We have not done the arrest solely on the basis of confessions. We will not arrest a person if we do not have sufficient evidence," Singh said replying to a barrage of questions.

After taking Talwar on remand, he said police would take him out for recovering the weapons used in the murder – a sharp edged weapon and possibly a hammer-like object.

Singh said Arushi had objected to her father's extra-marital affairs and was angry about it. She had discussed the issue with Hemraj. In the process, the two victims had also shared a close relationship.

On the night hours before the murder, Singh said, Talwar had returned from his clinic and had found the two in an ‘objectionable’ condition but not in a compromising position.

Hemraj had also discussed with his friends the doctor's alleged illicit relationship, which Talwar did not like. Hemraj had also feared for his life and had told some of his friends about that.

But the police official did not name with whom Talwar had illicit relationship but speculation was that it was with another doctor colleague.

He said on the pretext of talking to Hemraj, Talwar took him to the terrace and killed him by hitting his head with a heavy weapon and then used a sharp-edged weapon.

Then he came downstairs, had whiskey and around 1 am he killed Arushi by first hitting her head with a heavy object and then using a sharp-edged weapon to slit her throat.

Singh said police had several reasons to suspect the involvement of Talwar in the murders, one being that the couple was not prompt in calling the police and instead called people close to them to talk about the incident.

He said Talwar ‘sentimentally attacked’ the police when the murder has come to light and tried to mislead by saying they should not waste time at the crime spot rather go and look for Hemraj, who he said was the killer.

Another reason for suspicion was that they chose to dump Arushi's mattress on the neighbour's terrace. There was no forced entry.

"Talwar would not have been in sound sleep when the murder took place as he was talking on phone till 12 am. The area is peaceful and there is no traffic. So the slightest activity should have woken them up. It is not possible that a murder take place in the room right next to theirs and they did not hear anything," Singh said.

Suspicions were also raised because efforts were put into hiding Hemraj's body.

"The lid of the cooler was put on the body so that nobody could spot it and the door to the terrace was locked. Any killer who could have come did not bother to close the terrace door and lock it," he added.

Her mother Nupur was in their bedroom when the murder took place.

"Investigations are on and we have revealed to you details about which the probe is over. We have not done the arrest solely on the basis of confessions. We will not arrest a person if we do not have sufficient evidence," Singh said.

Lal said the details provided by former servant Krishna helped the police a lot in the case. "Hemraj used to tell him that he feared for his life as he knew about the doctor's affairs," he said.

The weapons used in the crime are yet to be recovered and police said Talwar's inputs would be important in finding them.

The police has been under tremendous pressure to crack the case ever since the failure of the Noida sleuths in finding Hemraj's body came to light.

The body was discovered by a retired police official who had come to the Talwar's residence to offer condolences.