He directed the ray of the torch upon the door on the immediate right of the stairhead.
"We're short-handed for this!" he muttered; "but it has to be risked now. Stay where you are and be on the alert. Watch those other doors." He tried the handle.
The door was locked.
To the next one he passed without hesitation. It yielded to his hand, and he flashed the light about a bare room, with half of the ceiling sloping down to the window. In the corner beyond this window a second door was partly concealed by the recess. The inspector stepped across the floor and threw the door open.
Then events moved rapidly.
Someone literally shot into the room behind him, falling with a crash that shook the place like thunder. Bang! sounded through the house, and a key turned in a lock!
Sheffield spun round like an unwieldy top, and saw the chauffeur struggling to his feet and rubbing his head vigorously.
The detective made no outcry, nor did he waste energy by trying a door he knew to be locked. He stood, keenly alert, and listened.
Footsteps rapidly receded down the stairs.
"Who did it? How did he get behind me?" muttered the dazed chauffeur.