Cindy Friedman, who served for nine years as chief of staff to the late Sen. Ken Donnelly, is in good position to be elected July 25 as his successor after winning a special election primary on Tuesday.
One of Friedman's opponents, Mary Ann Stewart of Lexington, congratulated her with a tweet after 9 p.m., calling her "the next senator" for a district that includes Arlington, Burlington, Billerica, Woburn, and four precincts in Lexington.
A Democratic Party official, communicating on background, said the exact vote tallies were still being counted but that Friedman had won Tuesday's primary.
State Rep. Sean Garballey of Arlington was the third candidate in the primary. There are no Republican or unenrolled candidates on the ballot.
Also on Twitter, Sen. Jamie Eldridge described Garballey as a "class act" and said Garballey had conceded the race and congratulated Friedman.
At 9:30 p.m., Democratic Party Chairman Gus Bickford congratulated Friedman and took a poke at Republicans.
"Cindy Friedman has been a strong progressive champion throughout her career and will continue to stand up for the working families of the Fourth Middlesex District in the Massachusetts Senate," Bickford said in a statement. "The people of Arlington, Billerica, Burlington, Lexington, and Woburn were fortunate to have three strong Democratic candidates running to fill the seat held for eight years by the late Senator Ken Donnelly. We look forward to working with Cindy in the Senate after the General Election in July, since the Republican Party couldn't even field a candidate to run for this seat."