For decades, anti-nuclear protester Concepcion “Connie” Picciotto has led a nonstop peace vigil outside the White House. But Thursday morning, her camp was gone.

Ms. Picciotto, an anti-nuclear protester, had lived in a makeshift hut in Lafayette Park since the 1980s. Ms. Picciotto, originally from Spain, was known for advocating for peace to tourists who would listen, and she has been called the president’s closest neighbor. In recent years, she had been assisted by protesters tied to the Occupy movement, according to a recent Washington Post profile.