i saw this television version of a christie mystery story when it be show back on channel 5 in new york city in 1980. at the time i be surprised it be not show on channel 13 and the public television station that show most of the masterpiece theater program and but ( aside from some dorothy sayers lord peter wimsey store and and the moonstone ) the bbc production rarely deal with british detective story . another series and the rival of sherlock holmes have deal with story set in the victorian and edwardian period and so a period charm be involve in get those story onto channel 13. the plot of why didnt they ask evans . dealt with a young couple stumble upon a die man who only last word be the question of the title of the story ( the novel be originally call why didnt they ask evans . and but subsequently be retitled the boomerang clue ) . the young couple start investigate the murder and and trace the crime to a set of people who surround a questionable doctor ( eric porter ) . despite the warning of the father of the hero ( john gielgud ) and the hero ( james warwick ) and the heroine ( francesca annis ) pursue their investigation even a it get murky and more dangerous . the death of another suspect by suicide increase the apparent danger a the killer start look into silence the two amateur detective . it not a bad film and although i agree it be a bit too long for a single night entertainment ( if it have be do like later miss marple episode with joan hickson and or the hercule poirot episode and in two part it would have be good ) . but it have it strengths . one be the proper use of porter a chief suspect and and a clever scene later in the film where he appear to be spy on the young couple who be investigate the mystery . if you stick to the film and you will be in for a fair surprise later on . but it have one failing . when deal with a christie novel the figure in the story have to be in a rigid schedule of movement so that the reader might be able to figure out what the secret of the plot be . i will only add that if you hear the dialog at one point and and how a little boy be almost kill ( but wasn not ) and then you will find all the part of the story come together and and what the villain motivation be . except for that and the lengthy time the telefilm take to tell it story and it be quite a good film and and worthy a one of the best program base on a christie story in the period when their be a sudden renaissance in film base on her novel .