would have gone about it in some other way. This one leaves too many
traces behind."

"Yes," Marion admitted.

"Well, the only reasonable conclusion you can reach with the robbery
and murder motives out of the way, is that the plotters wished to take
your father prisoner and hold him some place until they got what they
wanted."

"But what did they want?" asked the bewildered Marion.

"That's for your father to suspect and the police to find out," said
Helen shrewdly. "Personally, I haven't a doubt that the strike has
everything to do with it."

"What makes you think so?"

"The threatening letter that you received at the Institute. Show that
to your father tonight and suggest that he turn it over to the
police."

"I will," Marion promised. "In this new excitement I forgot all about
it. I didn't even show it to mother. Just as soon as papa finishes his
dinner, I'm going to show that letter to him. I'll go upstairs now and
get it. You wait here and be present when we talk it over, Helen.
You're so good at offering suggestions that maybe with you present we
can all work out some kind of solution of what has been going on."

Marion hastened up to her room and returned presently with both of the