State Sen. Leland Yee, who is a contender in the mayor's race, accused Lee's campaign of paying some of its workers in cash, a violation of election law.
Yee says one of the workers said he was promised a job at City Hall if he worked for lee's campaign.
"To see an individual running for mayor and perverting the process, trying to steal an election, to fake an election is something that is abhorrent," Yee said.
Lee's campaign denied Yee's charges and categorized them as an attack from a desperate candidate that is losing in the polls.
"Can you name the person he's made the allegations about? We have people working on our campaign. We are certain none of them have broken the law. We are certain we can go over the next two weeks and identify the voters we need to win," Lee campaign spokesperson Bill Barnes said.
This past weekend, seven mayoral candidates asked the Justice Department and the California Secretary of State to investigate supposed voter tampering by supporters of the mayor, some of which was recorded on video.