MANASSAS, Va. (AP) — A northern Virginia county is acknowledging that it underreported President Joe Biden’s margin of victory over Donald Trump there in the 2020 presidential election by about 4,000 votes, the first detailed accounting of errors that came to light in 2022 as part of a criminal case.

The admission Thursday from the Prince William County Office of Elections comes a week after prosecutors from the Virginia Attorney General’s office dropped charges against the county’s former registrar, Michele White.

Counts were also off in races for the U.S. Senate and U.S. House of Representatives, though by lesser margins.

In a statement, the county’s current registrar, Eric Olsen, emphasized that the mistakes did not come close to affecting the outcome of any race and “did not consistently favor one party or candidate but were likely due to a lack of proper planning, a difficult election environment, and human error.”

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In the presidential race, the county mistakenly shorted Biden by 1,648 votes, and overreported Trump’s count by 2,327 votes. The 3,975-vote error in the margin of victory was immaterial in a contest that Biden won by 450,000 votes in Virginia and by more than 60,000 votes in Prince William County.

In the U.S. Senate race, Democrat Mark Warner was shorted by 1,589 votes and Republican Daniel Gade was shorted by 107 votes. Warner won statewide by more than 500,000 votes.

And in a U.S. House race, Republican Robert Wittman was shorted by 293 votes. He won by more than 80,000.

The details released Thursday were the first extensive response about the errors since White was initially charged in 2022 with corrupt conduct, making a false statement and neglect of duty. Prosecutors from the office of Republican Attorney General Jason Miyares dropped the charges against White with little explanation, and court records lacked details on the alleged misconduct.

Only on Thursday did it even become public which candidates benefitted from the mistakes. Olsen said Thursday that he was restricted from being more forthcoming about the errors while the criminal case was litigated.

In a phone interview, Olsen said the majority of errors occurred in so-called “split precincts,” in which one precinct is home to two different congressional districts. The county’s voting system did not split the presidential vote by congressional district. The state system required them to be split that way. The errors occurred trying to conform the county data with the state requirements, he said.

Other mistakes highlighted faults in the county’s validation process. For example, Olsen said he first discovered the mistakes when he noticed that Precincts 607 and 608 displayed identical presidential votes. Someone had entered one precinct’s data into the other by mistake.

“It seemed like an obvious typo,” said Olsen, who replaced White as registrar and eventually reported the irregularities under his predecessor to state officials.

The case against White is the only criminal prosecution brought thus far by a special Election Integrity Unit that Miyares formed in 2022. Miyares’ office said the unit was created in part to fulfill a campaign promise “because Virginians expressed concerns to him about our elections as he traveled across the Commonwealth.” Critics, including the NAACP, said the unit was formed to pander to election deniers.

White’s attorney, Zachary Stafford, said the allegations that White was responsible for the incorrect numbers were disproven by pretrial statements from a government witness, and that prosecutors wisely dropped the charges. He said the county’s Electoral Board is the one that certified the election results, and White became a scapegoat.

“The board certified incorrect results and they, and the attorney general’s office, attempted to assign blame to Ms. White for their mistakes,” Stafford said in a written statement.

Virginia’s most recent redistricting has dramatically reduced the number of split precincts that caused Prince William County problems in 2020.

Olsen, the elections official, says new procedures and systems are in place to prevent errors.

“Mistakes are unfortunate but require diligence and innovation to correct. They do not reflect a purposeful attempt to undermine the integrity of the electoral process and the investigation into this matter ended with that conclusion,” Olsen said in a statement.