Let me first express an opinion.

You have not told all that you know of that evening's doings." This called for no reply and I made none.
"I can understand your reticence, if your knowledge included the fact of Miss Cumberland's heroic act and her sister's manner of death at the club-house." "But it did not," I asserted, with deliberate emphasis.

"I knew nothing of either.

My arrival happened later.

Miss Cumberland's testimony gave me my first enlightenment on these points.