The race for the second-largest prosecutor's office in the nation just got closer after more than 10,000 mail-in ballots were suddenly found just days before the important primary in Chicago. The progressive "Democratic insider" candidate for the Cook County state's attorney position has closed the gap with his competitor – who has received significant money from Republicans.

The Chicago Board of Elections added an additional 10,659 additional mail-in ballots after they were "mistakenly left out" after votes were due by March 19.

Max Bever – director of public information for the Chicago Board of Elections – told WBBM-TV, "In adding up the total number of Vote By Mail ballots the Board had received back so far, I mistakenly left out additional ballots that had been received back via USPS the evening of Monday, March 18."

Bever claimed, "I traded speed for accuracy in reporting out numbers this week as quickly as I could. I truly regret this error on my part and for the confusion that it has caused the voters of Chicago. I will share updated numbers only when they are accurate and verified."

As of Sunday afternoon, Eileen O’Neill Burke leads Clayton Harris III by a slim margin of 4,771.

"On Friday, thanks to the counting of mail ballots from Chicago voters, Harris whittled O’Neill Burke's lead, with a net gain of 1,366 votes," according to the Chicago Sun-Times.

Harris is seen as the more progressive candidate in the Democratic primary.

Harris said on the campaign trail, "Being a black man. I’ve been pulled over before for no reason. We can have safe communities without being racially profiled."

Harris has notched endorsements from labor unions, progressive leaders, and the Cook County Democratic Party.

Harris is a professor and former prosecutor.

O’Neill Burke categorized Harris as a "Democratic insider."

Meanwhile, Burke is seen as the Democratic candidate who will be tougher on crime.

O’Neill Burke said in January, "We have people in business leaving every day because of crime; make no mistake about it, the economic viability of Chicago is on the ballot this year."

O’Neill Burke said tackling "smash-and-grab" robberies was a top priority.

O’Neill Burke is a former Cook County prosecutor, defense attorney, and appellate court judge.

O’Neill Burke received donations from Republicans.

The Associated Press reported, "When it comes to fundraising, O’Neill Burke is ahead, with roughly double the amount of Harris, just under $2 million compared to roughly $750,000. Her sum includes money from top Republican donors."

The two candidates are competing to replace Kim Foxx – the current Cook County state attorney who declined to seek re-election after two terms.

Foxx is most known for her handling of Jussie Smollett staging a racist, homophobic attack hoax against himself.

Whoever wins the Democratic primary is expected to cruise to an easy victory in November.

Also running for Cook County state's Attorney are Republican former Chicago Alderman Bob Fioretti and Libertarian Party candidate Andrew Charles Kopinski.

After the Los Angeles County District Attorney's Office, the Cook County State Attorney's Office is the second-largest prosecutor’s office in the country with more than 3,000 employees.

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