The man's body was found in a hostel housing North Korean construction workers in the Pacific port of Vladivostok, near the North Korean border, on Thursday. Forensic experts said the man died of a brain injury.
"Investigators will have to establish whether the injuries were inflicted on the man intentionally or inadvertently," Vilen Zatsepin said.
Witnesses said the man had returned to the hostel with bruises on his face, saying he had fallen accidentally. But several hours later, his North Korean colleagues found him dead.
Two people from the Communist nation were beaten to death in Vladivostok in December in an attack investigators said was carried out by a group of teenagers.
Local police say attacks on foreigners have become more frequent in the Primorye Territory, which borders on China and North Korea and is home to thousands of migrant workers from those countries.
In 2006, 247 attacks were made on people of foreign appearance in the region, compared to 181 the year before. The statistics reflect a rise in xenophobic sentiment in the country as a whole.
Bloody interethnic clashes in northwest Russia last fall prompted authorities to impose restrictions on the number of foreign workers effective as of this year.
