Quotation from: The Secret Agent

Written by: Joseph Conrad

"You believe there were two men?" he asked, without uncovering his eyes.

The Chief Inspector thought it more than probable. In his opinion, the
two men had parted from each other within a hundred yards from the
Observatory walls. He explained also how the other man could have got
out of the park speedily without being observed. The fog, though not
very dense, was in his favour. He seemed to have escorted the other to
the spot, and then to have left him there to do the job single-handed.
Taking the time those two were seen coming out of Maze Hill Station by
the old woman, and the time when the explosion was heard, the Chief
Inspector thought that the other man might have been actually at the
Greenwich Park Station, ready to catch the next train up, at the moment
his comrade was destroying himself so thoroughly.