Andrei Galiakberov, spokesman for the Moscow police, described the roundup of some 1,200 people as part of a "pre-emptive raid" and said that some detainees are being investigated for possible criminal connections. Police also said that they found a car full of cash and unlicensed arms.
There was no sign in Biryulyovo of the crushed watermelons and overturned cars from the night before, but the smashed glass doors of the market remained closed for business.
Marina Ivanova, who runs a candy stall at the market, turned up for work despite the chaos of the day before. She had been helping customers on Sunday evening when she heard the rioters smashing glass and chanting racist slogans. Ivanova said she didn't take sides, but worried that the conflict could escalate. "They'll organize more people and come both sides."
Outside the shopping center, Elvin Khassan, a 25-year-old who had moved from Azerbaijan to Biryulovo to live with his relatives, faced off with an ethnic Russian man who was waving security camera shots of the suspected killer in his face, shouting, "You are hiding one of your own! Hand him over!"
Most of those in the crowd said they supported the rioters, who they said could be relied on more than the police to protect the neighborhood.
"They protected us, they are patriots," said Elvira Ablosimova, a retiree. "They had a little riot not a big one and attracted attention (to the issue)."
Nationalist parliament member Vladimir Zhirinovsky arrived at the scene, calling the stabbing a "deliberate provocation of the Russian people." But while many were star-struck by his appearance, the crowd remained skeptical.
Many average Russians accuse police and politicians of encouraging migrant workers because they are a source of cheap labor and bribe money, which the workers and employers pay to avoid the migration police.
"They arrested a (migrant) guy in my building no papers, nothing," said Alla Vasyanova, a mother of three who lived nearby. "He gave them some money, and goodbye. It's just a feeding trough. The politicians aren't on our side."
Yegor Shcherbakov, 25, was killed in a dispute over his girlfriend with another man as the couple returned home on Thursday. Sunday's rioters were protesting what they called impunity for the man's supposed killer. Police and investigators on Monday promised to find the man and bring him to justice.
Of the hundreds of suspected rioters arrested on Sunday, police kept only two in custody and fined 70 more. Dozens of police officers were injured, and five were hospitalized, police said.
The filmed beating of a plainclothes policeman at a market in Moscow spurred a widespread crackdown on the city's migrant workers in August.
Police stepped up patrols throughout the city on Monday to prevent a repeat of 2010 riots, when thousands of nationalists and soccer fans protested the killing of an ethnic Russian during a fight between soccer fans and men from the Caucasus.