He does not recognize any of the Rogues Gallery portraits as that of the man from whom he received the goods.
Pawnbrokers seldom identify crooks, for it is to their interest to plead a bad memory in this respect.
But Detectives Burke and Duvaney ascertain from one of their "stool pigeons" that Michael Ribbs, alias Padlock Mike, is in funds--that he and his "moll," who may be his wife or his mistress, are enjoying the fruits of Mike's labors.

And as Mike's specialty is burglary, Chief Manning rightfully decides that he is responsible for one or more of the recent robberies.
From this point the real detective work begins.

The chief assigns two of his really capable men, not to solve any one of the numerous burglaries that have been reported, but to ascertain the recent doings of Padlock Mike and to obtain evidence--legal evidence that will stand the test of the courts--with which to send the criminal to jail.

And the chances are that in convicting Mike, half a dozen mysterious burglaries will have been solved.
This is the ordinary routine of detective work.

Of course, there are innumerable variations, and yet not as many as most people imagine.
About eighty-five per cent.