Rohit Shekhar Tiwari, the son of former Chief Minister ND Tiwari, died of asphyxia as he was strangulated and smothered, PTI reported on Friday quoting an autopsy report. The Delhi Police on Thursday registered a case of murder into Rohit Tiwari’s death based on the autopsy report and transferred it to the Crime Branch.

Rohit Tiwari was brought dead to a hospital in New Delhi’s Saket area on Tuesday.

The autopsy was conducted by a medical board comprising five doctors of the All India Institute of Medical Sciences. “The medical board unanimously concluded that the cause of death in this case is asphyxia as a result of strangulation and smothering,” said Sudhir Gupta, head of the forensic department at AIIMS. “It is a sudden unnatural death, placed in the category of homicide.”

An unidentified police officer told The Indian Express that the doctors mentioned in the autopsy report that Rohit Tiwari died around 2 am on April 16. “Two bones in his neck were found broken,” the officer said. An autopsy was ordered after investigators found ligature marks on Rohit Tiwari’s neck, police said.

Special Commissioner of Police (Law and Order) RS Krishnia confirmed that the Crime Branch is investigating the case on the basis of autopsy report, reported Hindustan Times.

Unidentified police officials said officers of the Crime Branch visited Rohit Tiwari’s house on Friday and questioned his family members and domestic help. A team of forensic experts also visited the house. Officers are also going through footage from CCTV cameras installed in and around the house to ascertain the sequence of events and track people who entered the house.

On Tuesday, Ujjwala Sharma said her son’s death was natural. “I have no suspicion but I will reveal later what circumstances led to his death,” she had said.

ND Tiwari, a former Congress leader, and his son had both joined the Bharatiya Janata Party in January 2017 ahead of the Uttarakhand Assembly elections. Tiwari had died in October.