A senior federal prosecutor in Miami has withdrawn from an investigation into John O. Brennan, the former C.I.A. director, citing concerns about the legal viability of the politically charged case. Maria Medetis Long, a career Justice Department official overseeing national security investigations, notified lawyers for subpoenaed witnesses that she was no longer involved in the inquiry.

The investigation, led by U.S. Attorney Jason A. Reding Quiñones, has been part of a broader effort by Trump loyalists to pursue perceived political adversaries. Reding Quiñones, an ardent Trump supporter, has told senior Justice Department officials he plans to seek an indictment of Brennan in the coming weeks. The case centers on Brennan's 2023 congressional testimony about the intelligence community's assessment of Russian interference in the 2016 election.

This marks the second time internal dissent has plagued Trump's efforts to prosecute political opponents. The withdrawal raises questions about the strength of evidence against Brennan, who has been accused of making false statements about the C.I.A.'s role in handling the controversial Steele dossier. The case now tests acting Attorney General Todd Blanche's willingness to pursue politically sensitive prosecutions.