Tears: The killings have shaken local Ukrainians
One of their number is accused of brutally murdering his pregnant wife, three-year-old son and four other members of his family.
Police have launched a nationwide manhunt for 27-year-old Nikolay Soltys and are offering a $10,000 reward.
"He's making a black mark on our community," Eugene Kovalenko told the Associated Press.
Kovalenko and his father run a grocery named Arbat, where customers speak Ukrainian and Russian.
Roman Romaso, an 11-year resident and director of the Slavic Community Center, struggled to describe the horror sweeping through the immigrant community.
He told AP that he works with Ukrainian children to "avoid such sad stories".
Strong community
There are now an estimated 75,000 Ukrainians and Russians living in the Sacramento metropolitan area, out of an overall population of 1.8 million.
Most live in neighbourhoods outside the city centre.
The Eastern European immigrants have carved out a place for themselves there.
Last year, the city launched its first Russian Yellow Pages, with 300 advertisers, 90% of them Ukrainian and Russian.
The immigrant groups boast two TV companies, a pair of radio stations, several small newspapers, private schools, a half-dozen Russian-style stores and five Christian missions that work in the former Soviet Union.
Religious background
Nikolay Soltys was among the nearly 400,000 evangelical Christians and Jews who came to the United States in the 1980s.
The immigrants benefited from the so-called Lautenberg Amendment, which made it easy for religious groups alleging persecution in the Soviet Union to win refugee status in America.
Such refugees underwent a less rigorous immigration and criminal background process than other immigrants to the United States, according to a report in the Sacramento Bee newspaper.