AUSTIN — The state elections official who coordinated the matching of lists of driver's licensees with Texas voter rolls to see if they contain ineligible non-citizens has resigned.

Betsy Schonhoff, whom newly disclosed emails depict as the secretary of state’s office’s honcho of a nearly yearlong effort to match voter lists with databases at the Department of Public Safety, quit recently with no explanation, a spokesman for interim Secretary of State David Whitley said late Thursday.

“Betsy Schonhoff resigned last week after working at the Secretary of State’s office since 2012, and she didn’t provide any reason for her resignation,” Whitley spokesman Sam Taylor said in an email.

“She served as our Voter Registration Manager and we did not have any discussions with her about her resignation or her performance before she resigned.”

Efforts to reach Schonhoff were unsuccessful.

Praising her work were election administrators in a Republican-dominated county in North Texas, as well as a South Texas county that’s a Democratic bastion.

“She was beloved,” said Collin County elections administrator Bruce Sherbet, who has helped manage voter registration and elections in North Texas for nearly four decades.

“We hate to see her go,” said Sherbet, who said that on Tuesday, he heard a rumor Schonhoff had left state service. “I’m not really sure what the circumstances are but we wish her well."

Remi Garza, Cameron County’s elections administrator, also said he had no information on the reasons for Schonhoff’s departure.

"She was always very helpful and very respected by the voter registrars. She had always helped us out," Garza said.

For nearly three weeks, a political firestorm has raged over an advisory from Whitley’s office asking county elections administrators to check on whether nearly 100,000 Texas voters are possibly not U.S. citizens, and thus ineligible to vote.

At least 20,000 of the people identified had proved to DPS they were citizens at the time they registered to vote. Civil rights groups filed three lawsuits alleging that what Whitley calls a legally required “list maintenance process” is a prelude to an unwarranted purge of minorities from voter rolls.

At his Senate confirmation hearing last week, Whitley took heat, mostly from Democrats. A vote on his nomination was delayed.

On Wednesday, Whitley, a longtime aide to Gov. Greg Abbott, sent a letter to all 181 state lawmakers admitting to some shortcomings.

He said “more time should have been devoted to additional communication with the counties and DPS to further eliminate anyone from our original list who is, in fact, eligible to vote.”

Schonhoff, who Taylor said has been the voter registration manager her entire time at the secretary of state’s office, sent a series of emails to DPS driver's license division support manager Gayatri Vasan between March and September last year, according to a packet the Abbott administration provided to the Senate Nominations Committee.

“It’s fair to say she was our point person in interacting with DPS’s data team,” Taylor said.

In the past three weeks, various county elections administrators also described Schonhoff as their main contact at the secretary of state’s office.

Amid widespread confusion in the first few days after the advisory was issued, some county administrators described her as the only one in the state office from whom they could get any information.

Austin correspondent James Barragán contributed to this report.