Former City Hall aide Carlos Henriquez Tuesday night won the Fifth Suffolk seat held by Marie St. Fleur.

Barry Lawton, who came in 41 votes behind Henriquez in September's Democratic primary and waged a write-in campaign in the general election, conceded shortly after the polls closed. Lawton, an East Boston High School teacher, appeared at Henriquez's victory part at Restaurante Cesaria.

With 12 out of 19 precincts reporting, Henriquez was leading Lawton, winning 87.5 percent of the vote.

Roy Owens, a perennial candidate, was also waging a write-in campaign.

St. Fleur left the seat earlier this year to take a government relations job with the Menino administration.