The first red flags seemed obvious: Row after row of signatures written in the same handwriting. Some appeared twice. A few belonged to a rival candidate’s staffers.

Now, three of the people listed as signature collectors for S. Kathryn Allen’s campaign for an at-large D.C. Council seat have told The Washington Post that they did no such work.

Council member Elissa Silverman (I-At Large), who is running for reelection, is trying to knock Allen out of the race by alleging widespread fraud and technical errors among the more than 6,000 registered-voter signatures she submitted to qualify for the ballot.

A pre-hearing conference at the Board of Elections is scheduled for next week.

Allen, a first-time candidate backed by some D.C. business leaders, is running as an independent. Incumbent Anita Bonds (D-At Large) and independents Dionne Reeder and Rustin Lewis also are competing for the two at-large seats on the November ballot, along with some third-party candidates. Allen has questioned the validity of Reeder’s nominating signatures.

In Silverman’s challenge of Allen’s candidacy, three people who were listed on petitions as signature collectors have told The Post their information appeared to be forged.

Those sheets account for 1,247 signatures submitted by Allen, according to the Silverman campaign. The Allen campaign blamed the company it hired to gather signatures, Strategies for Change Group, which also worked for Lewis and for Traci Hughes, a former internal government watchdog who dropped her council bid after the firm presented her with petition sheets she said were obviously forged.

Allen spokeswoman Nona Richardson said the campaign collected 1,000 more than the 3,000 legitimate signatures needed to qualify for the ballot.

Leonard Howard Jr., who was listed as a signature collector on some of the petitions, told The Post he referred young adults in need of work to Strategies for Change when it was looking for signature gatherers for Allen but that he never collected names himself.

Howard said he was shocked when a friend alerted him to a Silverman campaign news release that accused him of signature fraud.

“That’s not in the realm of ethics that I operate in,” said Howard, who says he has done other campaign work for local politicians. “My reputation is very important to me.”

Tameka Lewter, who also was listed as a signature collector, said she responded to a Craigslist ad to gather signatures for Strategies for Change — but not for Allen.

“Somebody must have put my name on those forms,” said Lewter, who shared a copy of her signature that didn’t match the one on candidate petition sheets. “I just am kind of shocked at what’s going on. . . . Whatever kind of jobs that I sign up for, I work my hardest. I’m not going to forge anyone’s name on there; that’s illegal.”

The petition sheets warn that making false statements carries a penalty of up to $1,000 in fines and 180 days in jail.

DeShawnda Harris, the third person listed as a signature collector, replied to a text message asking whether she had worked on petitions for the Allen campaign by saying, “I have no clue what you are talking about and never heard of those people you’ve mentioned.” She declined to answer further questions.

Richardson, the Allen spokeswoman, said the campaign “did not have direct contact with those individuals.”

Khalil Thompson, head of Strategies for Change, told The Post last week that the Allen campaign did not retain his firm’s services to collect signatures, although he acknowledged people linked to his firm may have helped Allen on their own. But the Allen spokeswoman said the campaign did indeed hire the company.

Howard said it was Thompson who contacted him in search of signature collectors for the Allen campaign.

Thompson had no immediate comment this week. He has held a series of jobs in District government while also doing campaign work for council members Brandon T. Todd (D-Ward 4) and Robert C. White Jr. (D-At Large) in 2016 and several long-shot 2014 candidates.

As scrutiny of his company was ramping up this month, Thompson resigned from his nearly six-figure job as a top aide in the D.C. Department of General Services as of Aug. 17, a spokeswoman for the agency confirmed. A spokeswoman for Mayor Muriel E. Bowser (D) said Thompson was not asked to step down.

Political operatives and candidates in the District say it is not uncommon to be solicited by people willing to collect signatures for money. But they said aspiring politicians should use signature gathering as an opportunity to build up field operations.

“It’s an early test to see whether you can get your act together,” said Tom Lindenfeld, who worked as a strategist for Bowser and former mayors Adrian Fenty and Anthony Williams.

Chuck Thies, who worked on former mayor and current council member Vincent C. Gray’s campaigns, said any payments should be calculated using a daily rate, rather than paying for each signature collected. Several people told The Post that’s how Strategies for Change paid its workers.

“Paying per signature is the worst way to do it, because if I’m paying you per signature, what’s your incentive? To get as many signatures as possible and forgo quality, and that’s extremely problematic for campaigns,” Thies said.

Hughes, the former council candidate, called her experience a cautionary tale.

“For people like me who have never run for office before, you really have no idea who these companies are reaching out to collect the signatures, and you are trusting they are doing the right thing,” she said.