“My handicap, however, is that I have no justifiable excuse for taking a sample of blood from each of the people we suspect, or feel we might suspect.  For that reason I was waiting until one of the other detective methods should narrow the field of suspicion.  Now that there is the menace of another attempt to take a life I am forced to act.  To-morrow we will get samples of blood from everyone by artifice—­or force!

“Meanwhile—­” He hastened to continue, as though afraid we might interrupt to break his train of thought.  “Meanwhile, to-night, let us see if it is possible to accomplish something by the deductive method.

“Already I have gone into an analysis starting from the nature of the crime and reasoning to the type of criminal responsible.  The guilty man—­or woman—­is a person of high intelligence, added to genuine cleverness.  But for the results accomplished in this laboratory we would be without a clue; our hands would be tied completely.  Both Miss Lamar and Werner were killed by unusual poisons; deadly, and almost impossible to trace.  There was a crowd of people about in each case; yet we have no witnesses.  Now who, out of all our people with possible motives, are intelligent enough and clever enough to be guilty?”

Kennedy glanced first at me, then at Mackay.

“Manton?  Phelps?” suggested the district attorney.

“The promoter,” Kennedy rejoined, “is the typical man of the business world beneath the eccentricity of manner which seems to cling to everyone in the picture field.  Ordinarily his type, thinking in millions of dollars and juggling nickel and dime admissions or other routine of commercial detail is apart from the finer subtle passions of life.  When a business man commits murder he generally uses a pistol because he is sure it is efficient—­he can see it work.  The same applies to Phelps.”

“Millard?” Mackay hesitated now to face the logic of Kennedy’s keen mind.  “He was Stella Lamar’s husband!”

“Millard is a scenario writer and so apt to have a brain cluttered with all sorts of detail of crime and murder.  At the same time an author is so used to counterfeiting emotion in his writings that he seldom takes things seriously.  Life becomes a joke and Millard in particular is a butterfly, concerned more with the smiles of extra girls and the favor of Miss Faye than the fate of the woman whose divorce from him was not yet complete.  A writer is the other extreme from the business man.  The creator of stories is essentially inefficient because he tries to feel rather than reason.  When an author commits murder he sets a stage for his own benefit.  He is careful to avoid witnesses because they are inconvenient to dispose of.  At the same time he wants the victim to understand thoroughly what is going to happen and so he is apt to accompany his crime with a speech worded very carefully indeed.  Then he may start with an attempt to throttle a person and end up with a hatchet, or he may plan to use a razor and at the end brain his quarry with a chair.  He lives too many lives to follow one through clearly—­his own.”