Michael Banks, the national chief of the Border Patrol, announced in a letter to employees Thursday that he will retire from his post.His resignation comes after a Washington Examiner investigation into unethical behavior as a federal agent, according to four sources familiar with the matter.“After over 37 years in public service to the people of the United States [of] America, it is time for me to retire and return home to Texas to focus on my family and ranch,” Banks wrote in a letter to the workforce, obtained by the Washington Examiner.

Banks led the 19,500-member Border Patrol for nearly 16 months since President Donald Trump took office, but he had faced scrutiny in light of the revelations about his personal conduct. Customs and Border Protection has not yet announced Banks’s sudden retirement.

One senior administration official told the Washington Examiner that Homeland Security Secretary Markwayne Mullin met privately with National Border Patrol Council President Paul Perez on Wednesday to discuss Banks, in light of a second news story officials anticipated would come out on Thursday and paint Banks in a negative light. Perez and the union were heavily involved in selecting Banks to lead Border Patrol when Trump took office.