A top adviser to Beto O’Rourke, Becky Bond, has split with his campaign, an O’Rourke spokesperson confirmed.

Bond, a longtime progressive activist and organizer known for her work on O’Rourke’s 2018 Senate bid against Republican Ted Cruz, left the campaign along with her deputy Zack Malitz. Malitz worked closely with Bond on Sen. Bernie Sanders’ first presidential campaign in 2016.

The departures come as O’Rourke, the former Texas congressman, has sought to professionalize a campaign operation that was, in its earliest days, small and freewheeling. O’Rourke announced his run for the presidency less than a month ago.

In March, he recruited Jen O’Malley Dillon, a veteran operative who served in top leadership roles for Barack Obama in 2008 and 2012, to serve as his campaign manager.

In Washington, O’Malley Dillon’s hiring was taken as a sign that O’Rourke’s once-skeletal campaign was taking on a more professional cast, moving past the relatively small team that had helped propel him to his narrow loss in the Texas Senate race. Democratic strategists see O’Malley Dillon as an organized and evenhanded counterbalance to O’Rourke, who is known for his spontaneity and rejection of traditional campaign tactics, like the use of consultants and pollsters.

Chris Evans, a spokesperson for O’Rourke, did not address questions about the reasons for the departures or whether Bond and Malitz left voluntarily.

Evans said that Bond and Malitz, who worked for O’Rourke during the 2018 Senate race, only served as employees on a “temporary” one-month basis. Democratic operatives who have worked with Bond this year say she considered herself a central part of O’Rourke’s 2020 operation.

In a statement about her and Malitz’s departure to BuzzFeed News, Bond said it was “time for us to move on to other challenges.”

“Launching a presidential campaign without a big staff or even a campaign manager was no easy feat and it took everyone pitching in,” she said. “We’re proud to have been part of the team of deeply dedicated staff and volunteers who nearly pulled off a historic upset in the 2018 Texas Senate race and broke records launching Beto’s campaign for the presidency.”

They remain “volunteers” for the O’Rourke campaign, according to Evans.

“They were not only instrumental to the historic Texas Senate race but they agreed to help get us off the ground in this monumental undertaking of running a grassroots campaign for president in every part of the country,” Evans said in a statement on Saturday. “Becky and Zack remain close friends of the campaign, and true to form, they have already joined our army of grassroots volunteers who are signing up for shifts and committing to electing Beto president.”

Bond is a well-known organizer in progressive circles, serving as political director of Credo, a San Francisco–based activist group that aimed to push Obama to the left during his administration, before joining the Sanders campaign in 2016. On that race, she and Malitz helped build the Vermont senator’s “distributed organizing” program, which aimed to build volunteer leadership networks in areas of the country where the campaign lacked staff.

She and Malitz committed to support O’Rourke’s team in 2020 at a time when some progressives, including a handful of Sanders allies, were critical of the Texas congressman. Several of Sanders’ former advisers still work for O’Rourke.

As a presidential candidate, O’Rourke has tacked more toward the center of the party, saying early in his campaign that he was “no longer sure” that the single-payer "Medicare for All" bill written by Sanders, which he said he supported in his Senate race, was “the fastest way” to achieve universal health care. He's instead backed a plan that gives people the option to buy into Medicare.