“Thus, Medvedev and his companions remain unpunished,” she added.

The New York Times spent several weeks interviewing Mr. Medvedev and researching his personal history since he left the front in November and went into hiding in Russia. His account of his military service has contained contradictory or unverifiable claims. Some basic facts of his life, however, have been corroborated by public records and interviews with acquaintances.

The weight of this evidence shows that Mr. Medvedev enlisted with Wagner in July 2022, two days after finishing his latest prison sentence.

Wagner’s founder, Yevgeny V. Prigozhin, in April called Mr. Medvedev a “jackass who spent two days in Wagner, who can’t identify anyone.” After his escape to Norway, Mr. Prigozhin called him dangerous. He has not publicly threatened Mr. Medvedev.

In an interview in Oslo, Mr. Medvedev described his new living conditions, provided mostly by the Norwegian state. According to him, they include a house, home visits by a Norwegian language teacher, an integration assistant, ski and mountain bike trips, and “Taco Saturdays” with a personal security detail.

He also claims to be a subject of a bidding war between filmmakers, an assertion that could not be verified.