I have drawn certain conclusions ”yes. Summerhaye was still looking rather sceptical, but Japp continued his scrutiny of Poirot. 
Summerhaye was without a doubt and looked completely convinced. 
mnli hypothesis: Summerhaye was without a doubt and looked completely convinced.  premise: I have drawn certain conclusions ”yes. Summerhaye was still looking rather sceptical, but Japp continued his scrutiny of Poirot. 