He absolutely denied his identity with the man in the tweed suit, and swore he had not seen Mrs.Hazeldene since eleven o'clock in the morning of that fatal day.

There was no _proof_ that he had; moreover, according to Mr.Campbell's opinion, the man in the tweed suit was in all probability not the murderer.

Common sense would not admit that a woman could have a deadly poison injected into her without her knowledge, while chatting pleasantly to her murderer.
"Mr.Errington lives abroad now.

He is about to marry.

I don't think any of his real friends for a moment believed that he committed the dastardly crime.