Joe diGenova, appointed by Attorney General Todd Blanche to investigate alleged efforts by US intelligence and law-enforcement officials to undermine Donald Trump, reportedly resigned after a heated phone call with Blanche. The dispute has exposed tensions within the Justice Department and raised doubts about the future of a politically significant investigation.

Sources said disagreements concerned Blanche’s attempts to control the inquiry, including sending officials from Washington and denying diGenova access to a secure facility for classified material. The probe had reportedly reached dead ends, while career prosecutors were replaced or sidelined amid concerns about weak evidence; however, one Justice Department official disputed claims that it had stalled.