Uttar Pradesh government has ordered a magisterial investigation into the death of Mukhtar Ansari.
The inquiry will be conducted by a three-member team, said a government spokesman.
Mukhtar Ansari's son Umar Ansari claimed that the gangster-turned-politician was subjected to "slow poisoning" in prison.
A similar claim was also made by Ansari's brother and Ghazipur MP Afzal Ansari. However, the charge has been denied by the authorities.
Last week, Mukhtar, the former five-time MLA from Mau, submitted an application in Barabanki court, saying he was given some "poisonous substance" along with his food.
Ansari claimed that on March 19, his nerves and limbs started to pain after he consumed the food.
Police officials said that Ansari’s post-mortem is underway and is also being videographed. His viscera will be preserved if needed, the spokesman said.
Meanwhile, preparations are underway for his cremation at the Kalibagh burial ground in Mohamadabad in Ghazipur district.
The convoy carrying Ansari’s body will start its journey after Friday prayers, said a district official.
Section 144 has been imposed across Uttar Pradesh, banning large gatherings. Additional security personnel have been deployed in Banda, Mau, Ghazipur and Varanasi districts.
Mukhtar Ansari was brought to the Rani Durgavati Medical College in Banda from the district jail in "an unconscious state" on Thursday. A team of nine doctors attended him but he died of cardiac arrest.
On Tuesday, Mukhtar Ansari was hospitalised for around 14 hours after he complained of abdominal pain.
Ansari was born into a family with roots in the independence struggle. His grandfather served as the Indian National Congress President in 1927.
(Except for the headline, this story, from a syndicated feed, has not been edited by Odishatv.in staff)