The post-mortem report of Russian MP and businessman Pavel Antov indicates that he died of internal injury after a fall while his fellow traveller Vladimir Bidenov's death was due to a heart attack, police said on Wednesday.

Antov died after allegedly falling from the hotel's third floor here on December 24 while Bidenov, was found dead in his room on December 22.

Dr Lalmohan Routrai, Chief District Medical Officer (CDMO) of Rayagada told PTI that the post-mortem of Vladimir Bidenov, 61, was conducted at the District Headquarters Hospital on December, 24 and of Pavel Antov, 65, on December 26. The viscera of Bidenov has been preserved while that of Antov has not been preserved, the CDMO said.

Routrai said the post mortem reports have already been submitted to police. The viscera will be sent to forensic laboratory in Bhubaneswar.

The post-mortem report of Pavel stated that "he sustained a severe internal injury after falling from the third floor of the hotel," police said, adding that the post-mortem report of Bidenov stated that "he died of a heart attack".

Antov, a sausage tycoon-turned politician who had last June reportedly posted an anti-Ukraine war message on social media only to withdraw it later blaming the outburst on "technical error", had reportedly come to Rayagada along with Bidenov and two other friends on tourist visa to celebrate his 66th birthday, a police officer said.

Meanwhile, the other two co-travellers, Pansasenko Natalia (44) and Turov Mikhail (64) along with the tour guide arrived at the Crime Branch headquarters in Cuttack for questioning. Both of them have been asked not to leave the state.

All of them were questioned at the Bhubaneswar Crime Branch office on Tuesday night and Wednesday morning.

Odisha DGP Sunil Kumar Bansal on Tuesday ordered a CID probe into the "unnatural" death of two Russian nationals at the same hotel in Rayagada district.

Antov allegedly jumped off from the third floor of the hotel. On being informed, by the hotel staff, his guide Jitendra Singh rushed him to the district headquarters hospital (DHH) in an ambulance. However, Antov was declared dead on arrival, sources said earlier.

Meanwhile, the CID-Crime Branch team is scheduled to visit Rayagada on Wednesday to probe further into the mysterious death of the two Russian nationals on the direction of the Director General of Police.

Besides, DIG (South Western Range) Rajesh Pandit inspected the hotel in Rayagada where the Russian nationals were staying.