When the young clerk from the house agency came with the keys, he was much disturbed and bewildered after he got inside.

"They've made a bolt of it," he said. "That happens now and then, but there's something queer about this. What did they lock these doors in the basement for, and the one on the stairs? What did they say to you?" he asked Marco, staring at him suspiciously.

"They said they were obliged to go suddenly," Marco answered.

"What were you doing in the basement?"

"The man took me down."

"And left you there and bolted? He must have been in a hurry."

"The lady said they had not a moment's time."

"Her ankle must have got well in short order," said the young man.

"I knew nothing about them," answered Marco. "I had never seen them before."

"The police were after them," the young man said. "That's what I should say. They paid three months' rent in advance, and they have only been here two. Some of these foreign spies lurking about London; that's what they were."