Fulton County can't legally purge voters with vacant lots for addresses because it's too close to an election day, but questions are being raised about whether the county already violated federal law by starting the process.

Earlier this month the county mailed 2,400 letters telling registered voters that unless they prove their homes exist, they'll be erased from the rolls. That may have put doubt in some residents' minds about their eligibility, making it an act of voter suppression, according to a voter rights attorney.

"They can be sued for failing to comply with the [law]," said Laughlin McDonald, director of the American Civil Liberties Union's Voting Rights Project, "either by the federal government or a private person who has been targeted as a non-resident."

The Fulton elections board has its attorney, Lee Parks, looking into it. Parks told The Atlanta Journal-Constitution no laws were broken because no voters were ever removed from the rolls.

A motion to do that failed in a board meeting earlier this month.

"He's wrong," Parks said of the ACLU lawyer, "and we can defeat him in court."

Prompted by Georgia Secretary of State's Office investigation, the elections department was trying to clear out voters whose addresses are demolished public housing buildings, according to elections Director Sam Westmoreland. During the past two decades, Atlanta razed most of its public housing stock, and the issue of ineligible voters first came up after the 2009 mayoral runoff between Kasim Reed and Mary Norwood, which Reed won by 714 votes.

An investigation at that time, however, found that only 33 former public housing residents cast ballots.

The clampdown has already raised doubts about the integrity of Fulton elections, as well as the prospect of disenfranchising low-income, minority voters. Even if they moved and didn't update their address, registered voters may still be eligible to cast provisional ballots, McDonald said.

Questions have also been raised about why steps were taken to remove voters so close to the primaries. The National Voter Registration Act forbids any systematic purges within 90 days of a federal election, and several Congressional seats are on the July 31 primary ballot.

Westmoreland told the elections board Thursday that he started the process after the Secretary of State's Office threatened to take action against the county.

Half of the 2,400 people responded that they were living in housing that had replaced the demolished units. Staffers later determined through site checks that the other 1,200 or so people were claiming empty lots for residences.

Westmoreland apologized to the board for not keeping them apprised.

"It's not my desire to pull people off the rolls who ought not to be challenged," he said.

State Sen. Vincent Fort, D-Atlanta, has alleged the process is fraught with incompetence, pointing to elderly residents of the Atrium at College Town, a public housing high-rise, being among those informed that their building doesn't exist.

McDonald, of the ACLU, said the county could correct its mistake, and ward off any lawsuits, by sending 2,400 follow-up letters saying to disregard the first letters.

Westmoreland said he may do just that.