Lestrade tried to smile. He said, 'I believe we shall
only catch him if we have the luck to find him while
he is actually murdering some poor woman.'
He looked surprised when Holmes said, 'That is the first
sensible thing I have heard any policeman say about
these murders. We must catch him red-handed. A
drink, Inspector?' 'Yes, please, Mr Holmes. But who
can say when or where he will kill again?'
'I can,' Holmes said coolly. 'Let us look at the dates of
the murders. He kills, waits a week, kills again and
waits three weeks before the next murder. This
changes only when he has, as he tells us, 'no time to
rip', and has to kill twice on the same night. The
following week there is no murder. I tell you, Lestrade,
this is no crazy killer. This is a man who is following a
plan. He works only in Whitechapel, and in the early
hours of the morning.'
Lestrade looked helplessly at him. 'What shall we do?'
he asked.