C.D. Witherspoon, representing the Baltimore chapter of the Southern Christian Leadership Conference, discusses alleged irregularities with the city's April 26 primary at a news conference at the Baltimore City Board of Elections headquarters. (Josh Hicks/The Washington Post)

More than a dozen Maryland activists called Tuesday for the state to halt certification of election results from Baltimore’s April 26 primary and investigate alleged voting problems, a move that would cast doubt on state Sen. Catherine E. Pugh’s victory in the Democratic mayoral race.

The latest results show that Pugh, the state’s Senate majority leader, defeated former Baltimore mayor and runner-up Sheila ­Dixon by 2,574 votes out of 125,221 cast in the Democratic contest.

Some election watchdogs have questioned the integrity of the primary, citing concerns about vote tallies that went missing from several precincts for about 24 hours, polling stations that opened late and alleged conflicts of interest among election judges as well as problems with staff training and voting equipment, including shortages of ballots and ballpoint pens at some centers.

“This is about preserving the integrity of the democratic process in this city,” said C.D. Witherspoon, who represented the Baltimore chapter of the Southern Christian Leadership Conference at a news conference in front of the Baltimore City Board of Elections.

The activists, who say they are not working on behalf of any of the candidates in last week’s primary, sent a letter to Maryland Gov. Larry Hogan (R) asking him to intervene with an investigation through the state prosecutor’s office.

They said they had identified more than two dozen problems with last week’s primary, including campaign workers hired to work as election judges, voters who received the wrong ballots, eight precincts that submitted their results a day late, and former prison inmates who did not receive voter cards even though they had registered this year after the state legislature restored their voting rights.

“Given the totality of the irregularities, we cannot rely on the election results,” said J. Wyndal Gordon, the attorney who is serving as lead counsel for the effort.

Hogan’s office said the governor will allow the usual election-certification process to take place through the local election board and the state prosecutor’s office.

“He’ll be keeping an eye on it,” spokesman Doug Mayer said. “The governor supports fair and equitable elections and believes that any election that takes place in the state of Maryland should be completely free of any kind of irregularities or fraud.”

Baltimore Board of Elections Director Armstead B.C. Jones Sr. said some staffing and training issues stemmed from a rush to fill vacancies on the Friday before the election, after a firm that was hired to provide poll workers failed to fulfill its obligation.

“We filled them with a last-minute email blast,” he said. “We had to fall back on city workers. We may have been short 68 people at the end of the day.”

Jones said all of the poll workers were trained the day before the primary and should have known they were prohibited from working at a polling station if they were involved in a campaign.

He added that election judges sometimes misplace memory sticks and thumb drives that contain election results from their precincts, but the board ultimately tracked down the Baltimore results in question.

“It was a legitimate election,” Jones said. “Of course there are shortfalls, but they are human shortfalls that have nothing to do with the integrity of the election. I think people are just fishing.”

The protest sent to Hogan stated that the missing results cause concern about “whether or not the chain of custody was broken and if the votes . . . were in fact compromised.”

Jones said he had not been contacted by the offices of the governor or the state prosecutor.

The activists at Tuesday’s event included several Democratic candidates for the Baltimore City Council’s 5th District seat, including Betsy Gardner, Christopher Ervin and Kinji Scott. Isaac Schleifer won that race with 3,369 votes out of 10,360 cast.

G.I. Johnson, former president of the Baltimore NAACP, said the issues with last week’s primary could diminish public confidence in the election process. “It’s going to be extra tough to get voters to the polls now,” he said.

Statewide, election officials say they received few reports of glitches in Tuesday’s primary, which marked Maryland’s long-awaited switch to paper ballots tallied by scanning machines nearly a decade after lawmakers decided to ditch electronic machines that left no paper trail.