U.S. Border Patrol Chief Carla Provost is expected to leave her post by December, according to several high-ranking former Department of Homeland Security and union officials with first-hand knowledge of the plan.

Provost, the first woman to lead the 95-year-old federal law enforcement agency, will retire by the year’s end, wrapping up her 24-year career, the Washington Examiner has learned.

The 48-year-old lifetime Border Patrol employee has served as permanent chief for less than a year. She was acting chief from April 2017 through August 2018 and officially took over late last summer after Robert Perez was confirmed by the Senate as deputy commissioner of Border Patrol’s parent agency, Customs and Border Protection.

Provost has led the agency’s 20,000 employees during a turbulent time as the organization struggles to handle the more than half a million people apprehended while illegally crossing the U.S.-Mexico border in the first six-and-a-half months of fiscal 2019. It will also leave another hole in DHS, which has more than a dozen vacancies at the senior level.

“It’s not going well over there. The pressure’s outrageous,” said a former Customs and Border Protection leader who was aware of her forthcoming departure, who added she may leave earlier than December.

Two officials said Manuel "Manny" Padilla was most likely to take over when Provost leaves. Padilla is director of the Department of Homeland Security Joint Task Force West and served 30 years with Border Patrol. He was tapped in April to head the department's interagency emergency border cell.

Department of Homeland Security and Customs and Border Protection did not respond to requests for comment.

Provost joined the Border Patrol in her early 20s after working a short period as a police officer in her home state of Kansas. She worked in Texas, Arizona, and New Mexico. She went on to take over its Washington-based internal affairs office in 2015.

Customs and Border Protection Commissioner Kevin McAleenan credited her last August for her work in internal affairs and the lowering of firearm-related incidents even as assaults against agents jumped to a record high. However, an Intercept report last year showed assaults were being counted in a new way where each rock thrown at an agent counted as an assault.

Provost was endorsed by the National Border Patrol Council, the primary union for agents, at the time of her promotion to chief in early 2017.

“Carla is an agent's agent,” McAleenan said at the promotion announcement last August. “She's come up through the ranks.”

Since taking over Border Patrol as acting and permanent chief in early 2017, Provost has been on the receiving end of the Trump administration's attempts to go after unauthorized immigrants and thwart illegal immigration, including the family separations that took place during the "zero tolerance" policy.

Provost sat down with the Examiner last May and said one of her greatest frustrations was the amount of coverage on “anything that’s in a negative fashion."

“I would tell you it doesn’t make it into the media generally because it’s not sexy,” Provost said. “I have seen and I’ve done it myself. Border Patrol agents — they apprehend people. They’re hungry and they’re thirsty. They go through a drive-thru on their way to take them in and they use their own money to buy them food and something to drink. I, many a time back in the day, ran through — whether it was McDonald's usually in Douglas because there wasn’t a lot of options — but agents do those things."

On Monday, a 16-year-old unaccompanied Guatemalan boy died while in Border Patrol custody. The death marked the fourth minor to die in Customs and Border Protection custody this fiscal year and brought criticism from immigrant groups and Democratic lawmakers concerned about overcrowded conditions at government facilities on the southern border.

[Also read: Trump's top Border Patrol official explains the two crises America faces at the border]