'You are a true friend, Watson,' Holmes said at last.
'You came with me without a question. Did you
realize that someone was following us?'
'I thought so. But who?' 'Can you not guess?' 'No.'
'He calls himself Jack the Ripper.'
'Holmes!' For a moment I found it difficult to speak.
Then I asked, 'Did you see him through the window?
Where was he?'
'In the empty house opposite ours. He was watching
our rooms, Watson. He knows that I am looking for
him. We must be very careful. He is one of the most
dangerous criminals in Europe.'