A career Justice Department lawyer who has specialized in organized-crime issues was recently transferred from the deputy attorney general’s office to another division because he failed to inform officials of a September 2016 meeting with the author of a controversial dossier on then-candidate Donald Trump, people familiar with the matter said.

Bruce Ohr, 55 years old, was never involved in the Justice Department’s probe into Russia’s meddling in the 2016 election, according to current and former Justice Department officials....