They took a dozen steps in silence. Then she said:
“Who was it speaking to Mr. Parrish in the library?”
“Undoubtedly Mr. Greve,” replied the man without hesitation.
“Why undoubtedly?” asked the girl.
“It could have been no one else. We know that he left you hot to get at Mr. Parrish and have words with him. Bude heard them talking with voices raised aloud....”
“But if the door were locked?”
“Mr. Parrish may have opened it and locked it again, Mr. Greve getting out by the window. But there are no traces of that ... one would look to find marks on the paint on the inside. Besides, a little test we made this morning suggests that Mr. Greve spoke to Mr. Parrish through the window....”
“Was the window open?”
“Yes, Miss, it probably was. The fire had been smoking in the library. Mr. Parrish had complained to Bude about it. Besides, we have found Mr. Parrish’s finger-prints on the inside of the window-frame. Outside we found other finger-prints ... Sir Horace’s. Sir Horace was good enough to allow his to be taken.”
The girl looked at the detective quickly.