Russia's consul general in Dubai questioned the report on Wednesday, saying police had said Yamadayev was shot dead on March 28 in the car park of a luxury seaside apartment block in Dubai, and buried at a local cemetery.
The Kommersant newspaper reported that Sulim had tried to declare a vendetta against President Ramzan Kadyrov and his cousin, State Duma member Adam Delimkhanov, via an influential Muslim cleric in Chechnya. However, Isa Yamadayev told the paper that the mullah refused to convey the message to the clan, as is required by tradition.
Mullah Nurid-hadzhi Kimayev in the Russian North Caucasus republic's second largest city Gudermes confirmed he received a phone call several days ago from a man who claimed to be Sulim.
"I lived next door to the Yamadayev brothers for a long time, and I know the family very well. But I have not seen or heard from Sulim for years and could not be sure I was speaking to him," the cleric told the paper, adding he would not have conveyed the message anyway as he did not want to be part of a blood feud.
Sulim, who served as the commander of Russia's Vostok battalion in Chechnya, fled the republic last year after a clash between his troops and Kadyrov's guards.
The paper said "the procedure was not observed" and as a result the blood feud was not "formally" declared.
Isa Yamadayev told the paper he personally would seek legal punishment for those behind the attempt on Sulim and the murder of their elder brother Ruslan in Moscow last September.
In the latter case, Russian police have arrested one suspect, a driver, and several Chechens, including Delimkhanov, have been put on an international wanted list as part of the probe into the Dubai shooting. The lawmaker strongly denied any involvement in the case. Russia's constitution does not allow the extradition of Russian nationals accused of crimes in other countries.
Isa said Sulim was only injured and is now in a Dubai hospital under police guard, adding that they were in contact via the Internet, the paper reported.
The Russian consul general in Dubai, Sergei Krasnogor, said: "Dubai police officials, including the police chief, have repeatedly confirmed to me that Sulim Yamadayev had been killed and buried at a local cemetery."
Russian diplomats earlier acknowledged they had not been provided with documentary evidence of Sulim's death.