Startled by the question, Dr. Raines needed time to deliberate. He excused himself to shower. When he returned downstairs, he coolly took the offensive.

“I’m so angry about what I’ve been reading in the press about the F.B.I. and the abuses that have taken place that I’m not going to talk to you about any of it,” Dr. Raines said to the agents, his wife recalled on Thursday. “I’m not going to make your job any easier. I’m not going to answer your question.”

For nearly two decades, no one from the government asked him the question again. And so no one learned that he had been one of eight antiwar activists, including his wife, who took part in the burglary — and that he had driven a getaway car, the family station wagon.

As he hid in plain sight, Dr. Raines remained mute about the episode, the couple’s last protest against the war in Vietnam.

“We didn’t need attention, because we had done what needed to be done,” Dr. Raines told The New York Times in 2014. “The ’60s were over. We didn’t have to hold on to what we did back then.”