Sergey Mamontov, 50, was questioned at a police station in New York's Brooklyn borough, and police said they expected to charge him with murder, the New York Daily News reported.
A police source told the newspaper the 55-year-old victim, whose name was not released, had been living in the apartment with Mamontov for about eight months, and that there had been several 911 calls from both men, complaining about each other.
"He said his roommate was noisy, that he brought in friends, including homeless guys, and other inappropriate friends," an unidentified source told the Daily News. "They kept him up at night."
Another source said Mamontov "was very meticulous, very methodical" in cutting up the victim.
"He cleaned up afterwards. He put the body parts in the refrigerator ...," the source said. "He didn't know what his next move was. He didn't know where he was going to take the body parts.
"He was very matter of fact. He didn't want to say anything at first, but once he started talking, he wouldn't shut up."
A neighbor, Eugene Lisoukova, told the newspaper Mamontov had a number of roommates in the past several years, and two weeks earlier asked him about the new roommate.
Mamontov allegedly told his neighbor, "Yes, but he will go away soon and no one will see him anymore."