Marguerite knew the Reds suspected her, but she tried to tell herself they had no evidence against her. Then one night in early April as she walked from work at the Foreign Office, a soldier stopped her in the street and demanded her name.
When she told him, he replied, “You’re arrested.”
The soldier led her to the Cheka headquarters, a large building on Lubyanka Square that had once housed a life insurance company. The sign above the doorway still read: “It is prudent to insure your life.”
Marguerite was placed in a sparsely furnished cell that once had been a dorm room for workers of the insurance company. She did not panic. She threw her fur coat over the board bed and slept until she was awakened by someone who turned on the light and stared at her through a peephole in the door.
Unbeknownst to her, McCullagh and Karlin had also been arrested that night. Marguerite later vaguely described the experience of waiting for her interrogation, but McCullagh provided a vivid account of what the suspense was like.
For the most part, his room was silent, “broken only by terrifying sounds, with which they surrounded me, and also the disquieting sights they sometimes permitted me to see,” he wrote. “I could not help but reflect on the cruelty of treating delicate women in this way. And delicate women were so treated. Mrs. Harrison of the American Associated Press had been arrested in the Savoy the same day as myself, and, as I afterwards learned, was at that very moment being subjected to the same terrible regime in another part of the building.”
Finally, in the afternoon, a guard appeared at her cell and ordered her to follow him. He escorted her through a maze of corridors to another part of the building where she was admitted to a large room furnished with leather armchairs, a large desk, bookshelves, and walls covered in diagrams resembling genealogical charts that showed alleged foreign spy networks in Russia. At the desk sat a slender man dressed in black —Solomon Mogilevsky, head of the foreign section of Cheka.
“We have been watching you for some time, Citizeness Harrison,” he said, addressing her in impeccable French. “We are fully aware of the nature of your mission.”
Marguerite didn’t flinch. “What do you mean?” she asked.
“We know perfectly well that you are here as a representative of the American Secret Service. You acted in a similar capacity in Germany last year. We have reports from both America and Germany to prove this.”
Mogilevsky proceeded to describe her movements in detail. She was amazed, but kept her composure. “Where is your proof?” she demanded.
Mogilevsky opened a briefcase and pulled out a document—the report she had written on Julius Hecker’s Bolshevik activities that she had given to the American attaché in Switzerland. After the State Department arrested Hecker and sent him back to the United States for questioning, he soon realized who was responsible for reporting his activities. Two weeks before Marguerite’s arrest, Hecker’s wife had appealed to the embassy in Berne for her husband’s release. Apparently, Hecker’s friends in Russia tipped authorities to Marguerite’s mission, and a mole in the Military Intelligence Division had supplied the report as proof.
Marguerite knew it was useless to deny the accusation in face of the evidence. “Very well. I acknowledge it. I am an agent of the United States government,” Marguerite said. “I suppose you will have me deported.”
Mogilevsky smiled slyly. “No, my dear lady, you know too much for that.”
Suddenly, the access she had been given to Bolshevik leaders and uncensored news from the provinces made sense. She had been trapped.