"Besides," Britz went on, "we have evidence of a reconciliation between
Collins and his wife. It may be simply a pretense, an effort to delude
the police. But from what we have gathered about Mrs. Collins, it is
unlikely that she would consent to live with a murderer, even though she
did not denounce him openly."

"But the reconciliation occurred last night--they went to the opera
together," reminded Greig. "The murder was committed this morning."

Britz bent forward in his seat, favoring his assistant with a tolerant
smile.

"Only one reason could prompt a woman of Mrs. Collins's caliber to
return to a man of Collins's type," he said. "She might hesitate a long
while before leaving her husband. But once she took the decisive step,
nothing short of a desire to save the life of the man she loved could
induce her to return. Don't you see the situation? She must have had
knowledge that Whitmore was coming back. And, isn't it more than likely
that before she consented to return to her husband she exacted a promise
from him not to execute the vengeance which he had threatened?"

"It's certainly an amazing tangle," admitted Greig. "And I had thought
that it was all clear as day!"

"No, Greig," smiled Britz, "it isn't very likely that we're going to
arrest Collins. But we'll go to the woman's house and watch
developments."

The two detectives proceeded uptown in the subway to Ninety-first
street, then walked slowly down Broadway, turning west at Ninetieth
street.

As they turned the corner they became aware of an excited group of men
and women in front of a big, gray-stone house, the name of which
corresponded to that given by the visitor at Headquarters.

The crowd was gathered in front of the entrance, talking excitedly, each
asking the other what had happened. No one seemed to know precisely what
the excitement was about, but that something extraordinary had occurred
was plainly evident.

Britz and Greig plunged into the hallway and pushed the elevator button,
but the car did not descend. They waited impatiently a minute or two,
then proceeded up the stairs.

On the third floor they found most of the tenants of the house massed in
front of the closed door of one of the rear apartments.

"We are officers," said Britz, forcing a lane through the crowd. "Who
lives in there?"

"A woman named Strong," someone answered.

Britz pressed a finger firmly against a button set in the jamb of the
door, and, in respons