To manage a drunken man, or one half-drunk, requires exceptional tact.

Once his suspicions are aroused, it is impossible to allay them.
Even now it was evident to the detective that Collins wasn't talking as freely as he pretended to be.

He still retained a sufficient amount of caution not to plunge into the details of the murder itself.

What he said of his wife's relations with Whitmore was simply a repetition of statements he had made at the club and elsewhere before Whitmore's death.

Plenty of witnesses could be obtained who would testify to having heard Collins threaten to kill the merchant.