All this I had learned from visits to a studio with the Star’s photoplay editor.  I was anxious to impress my knowledge upon Kennedy.  He gave me no opportunity, however, but wheeled upon Mackay suddenly.

“Send in the electrician,” he ordered.  “Keep everyone else out until I’m ready to examine them.”

While the district attorney hurried to the sliding doors, guarded on their farther side by one of the amateur deputies he had impressed into service, Kennedy swung the stand of the arc he had used back into the place unaided.  I noticed that Doctor Blake was nervously interested in spite of his professional poise.  I certainly was bursting with curiosity to know what Kennedy had found.

The electrician, a wizened veteran of the studios, with a bald head which glistened rather ridiculously, entered as though he expected to be held for the death of the star on the spot.

“I don’t know nothin’,” he began, before anyone could start to question him.  “I was outside when they yelled, honest!  I was seeing whether m’lead was getting hot, and I heard ’em call to douse the glim, an’—­”

“Put on all your lights”—­Kennedy was unusually sharp, although it was plain he held no suspicion of this man, as he added—­“just as you had them.”

As the electrician went from stand to stand sulkily, there was a sputter from the arcs, almost deafening in the confines of the room, and quite a bit of fine white smoke.  But in a moment the corner of the library constituting the set was brilliantly, dazzlingly lighted.  To me it was quite like being transported into one of the big studios in the city.

“Is this the largest portion of the room they used?” Kennedy asked.  “Did you have your stands any farther back?”

“This was the biggest lay-out, sir!” replied the man.

“Were all the scenes in which Miss Lamar appeared before her death in this corner of the room?”

“Yes, sir!”

“And this was the way you had the scene lighted when she dropped unconscious?”

“Yes, sir!  I pulled m’lights an’—­an’ they lifted her up and put her right there where she is, sir!”

Kennedy paid no attention to the last; in fact, I doubt whether he heard it.  Dropping to hands and knees immediately, he began a search of the floor and carpet as minutely painstaking as the inspection he had given Stella’s own person.  Instinctively I drew back, to be out of his way, as did Doctor Blake and Mackay.  The electrician, I noticed, seemed to grasp now the reason for the summons which undoubtedly had frightened him badly.  He gave his attention to his lights, stroking a refractory Cooper-Hewitt tube for all the world as if some minor scene in the story were being photographed.  It was hard to realize that it was not another picture scene, but that Craig Kennedy, in my opinion the founder of the scientific school of modern detectives, was searching out in this strange environment the clue to a real murder so mysterious that the very cause of death was as yet undetermined.