Thousands of Fulton County voters didn’t get the precinct cards when they were supposed to, or at all, said Richard Barron, the county’s director of Elections and Registration.

On election day, that led to complaints from residents who went to vote at one precinct only to find that their precinct had moved.

In addition to those cards that arrived late, about 850 precinct cards were delivered to polling locations instead of residents. And Barron said the county had between 30,000 and 40,000 precinct cards that were returned, with addresses that appeared to be good.

The Secretary of State’s office has opened an investigation, said Candice Broce, a spokeswoman for the state office. The U.S. Postal Service is also looking into it, spokesman Rick Badie said in a statement.

To read more about why some residents didn't know where to vote ahead of the March 1 presidential primary election, click here.