“Mr. Berger made his choice to enlist in 1943 in the German military,” Mr. Rosenbaum said in an interview on Friday.

Mr. Berger then made another choice, Mr. Rosenbaum said, to not request a transfer when he was assigned to a sub-camp overseeing prisoners in the Neuengamme concentration camp system near Meppen, Germany.

In a statement, another federal prosecutor, Brian A. Benczkowski, said that Mr. Berger was “part of the SS machinery of oppression that kept concentration camp prisoners in atrocious conditions of confinement.”

While Mr. Berger’s story is not quite over — he has 30 days to appeal the deportation order — federal prosecutors are “just about finished” with such Nazi-era cases, given the advanced ages of the suspects, Mr. Rosenbaum said.

And that means the likely end of a specific kind of high-stakes detective drama, heavy with the weight of history and horror — cases that played out over the years in the long shadow of World War II and the Holocaust, as collaborators were discovered and rooted out from often-cozy American existences that had normalized them and scrubbed them of their complicity.

The federal government has brought forward 133 such cases over the last four decades, and won 109 of them. In most of the others, Mr. Rosenbaum said, the suspects died or became medically incapacitated and were unable to stand trial before their cases were resolved.

The federal target list included well-known men like Valerian Trifa, the Romanian Orthodox archbishop accused of being a Nazi sympathizer, who left the United States in 1982 to avoid deportation. Arthur Rudolph, a developer of the Saturn 5 rocket for the federal space program, left the country in 1984 after the Justice Department accused him of “working thousands of slave laborers to death” in a German rocket factory during the war.