 Police first called at Armstrong's flat on 1 July while conducting initial door-to-door inquiries during which residents were asked to answer a questionnaire aimed at tracing her last movements.On 2 July, they returned while carrying out "cursory searches" of houses in the area.On 3 July two detectives spoke to Armstrong; they noticed that his previously "co-operative, friendly and helpful" demeanour had changed, and that he then appeared "very shifty, on edge and looking very worried".