"Sulim Yamadayev was buried two days ago in Dubai by his brother Isa. This has been confirmed by Isa," Kadyrov told reporters in Grozny.
Earlier Isa Yamadayev and some other relatives said Yamadayev was alive.
Yamadayev, who headed Chechnya's Vostok battalion, was shot by a lone gunman in the underground car park of the Dubai apartment block where he lived early on Saturday.
Earlier Russia's Consulate General told RIA Novosti that at least seven people had been detained in connection with the murder, all of whom had Slavic surnames.
Yamadayev was officially dismissed from his post as commander of the Defense Ministry's Vostok battalion last August over alleged involvement in the 1998 abduction and murder of a Chechen businessman.
The killing of Yamadayev is the sixth in a series of killings of Chechen exiles in the past year.
Sulim's brother, Ruslan Yamadayev, a former member of the Russian parliament's lower house, was gunned down in central Moscow last September. He was a prominent opponent of Chechen President Ramzan Kadyrov, who has denied any involvement in the killing.
A cemetery worker told RIA Novosti on Wednesday that Yamadayev, murdered over the weekend in Dubai, has been buried at the Al Quoz cemetery in Dubai.
