* Advocacy group says suspects Uzbek's death was revenge killing
* Earlier killing of ethnic Russian led to riots, nationalist threats
* Many Muscovites resent influx of mostly Muslim migrants
MOSCOW, Oct 16 (Reuters) - A migrant worker was found stabbed to death on Wednesday in a Moscow neighbourhood rocked this week by race riots, in what a community leader suggested was a revenge attack for the killing of an ethnic Russian.
Last Thursday's slaying of Yegor Shcherbakov in Biryulyovo, heavily populated by immigrants from ex-Soviet Central Asian and Caucasus states, unleashed the capital's worst race riots for three years.
Before a suspect in Shcherbakov's death was arrested on Tuesday, crowds of Russians had roamed Biryulyovo's streets hunting for non-Slavic men who matched a police description of his alleged killer.
A police source said the corpse of a citizen of predominantly Muslim Uzbekistan was found in the district on Wednesday, news agency Interfax reported.
"We warned migrants to be careful of nationalist scum, and now the body of an Uzbek has been found," Mukhamad Amin Madzhumder, head of the Federation of Migrants of Russia, said.
Migrant labour has played a significant economic role in Russia during an oil-fuelled boom that took off around the time President Vladimir Putin came to power in 2000.
But many Muscovites resent the influx into the capital of migrant labourers from mostly Muslim ex-Soviet states, and have called for tougher policing and visa restrictions.
State TV showed footage of 25-year-old Shcherbakov's alleged killer - from Azerbaijan and named by police as Orhan Zeynalov - being detained in the city of Kolomna on Tuesday and flown to Moscow by helicopter.
In a video released by police, Zeynalov admitted stabbing Shcherbakov but said he had acted in self-defence.
In a third day of unrest in Biryulyovo, police late on Tuesday detained hundreds of nationalist youths who had gathered to protest Shcherbakov's killing.
It was the worst outbreak of race-related unrest in Moscow since December 2010, when several thousand rioted near the Kremlin. (Reporting by Alissa de Carbonnel; Editing by Thomas Grove, John Stonestreet)