The Delhi Police on Sunday said they were close to cracking the murder case of Rohit Shekhar Tiwari – the son of former Uttar Pradesh chief minister ND Tiwari.

Investigators said they have identified the prime suspect in the case who they claimed was not an outsider. Police said they would arrest the suspect soon.

Shekhar’s wife Apoorva was questioned by Delhi Police throughout Sunday.

“We have got sufficient and unambiguous evidences against the suspect. A formal announcement on the arrest will be made soon,” said deputy commissioner of police (crime) Joy Tirkey, who is leading the investigating team.

Shekhar was found dead on Tuesday and the report of an autopsy on Friday said that there were signs that he died of “asphyxiation due to ante-mortem strangulation and smothering” prompting the police to start a murder investigation.

Shekhar’s wife Apoorva and his half-brother Siddharth were at home, along with the three servants, at the time of his death. Police said they are questioning the five people since they did not suspect the role of any outsider.

On Sunday, a 10-member investigating team — led by DCP Tirkey — reached Shekhar’s Defence Colony house, the place where the crime took place, to look for clues. A forensic team also visited the house, for the second time in as many days, to collect fingerprints and other forensic evidence from the cars belonging to Shekhar and other family members. The call detail records of cell phone numbers of the family members and those who were in touch with them before and after the alleged murder are also being analysed.

An investigator, on the condition of anonymity, said that they have so far scanned the footage of all the nine CCTV cameras installed at Shekhar’s house and found that nobody had entered or left the house between 11pm on Monday till late on Tuesday morning. “We have reasons to believe that Shekhar was administered an overdose of sleeping pills so that he could not resist. He used to take sleeping pills every night. But somebody overdosed him,” the officer said.

As per the contents of the first information report (FIR), the Defence Colony police station received a call regarding Shekhar’s death at 6.55pm on Tuesday from a private hospital where he was rushed in an ambulance by his family members and employees after they found him unconscious in his room.

The hospital authorities told the police that they had received an ambulance call from Shekhar’s distant relative to attend to the patient at home. “Patient was found unconscious inside the car with no sense of life, no pulse, no spontaneous breathing, pupils fixed and dilated and bleeding from the nose,” the FIR read.

Shekhar was declared brought dead at the hospital. His autopsy was conducted by a panel of doctors at AIIMS mortuary on Wednesday. “A case was registered after the autopsy report revealed the cause of death as ‘asphyxiation due to ante-mortem strangulation and smothering’,” said the officer.

First Published: Apr 22, 2019 09:01 IST