There was a short and vehement dispute.
Possibly the baronet guessed the object of this unexpected appearance.
There may have been a struggle.

Then the knife was sent home, with such singular skill that the victim fell without a word, a groan, to arouse attention.

The murderer made off down the avenue, but he was far too cold-blooded to run away and encounter unforeseen dangers.

No; he waited among the trees to ascertain what would happen when his victim was discovered, and frame his plans accordingly.

It was then that he saw Helen Layton and David Hume.