Mortenson continued to read the accounts for some minutes; then suddenly he was interrupted by a loud knock on the door. He jumped nervously, laid the paper aside and went to it. His hand shook on the knob and his lips twitched. He swung the door wide open, to find himself confronted by two burly detectives. They displayed their badges with little formality. But Mortenson knew what they were after.
"Come right in, gentlemen," he invited quickly. "I've been expecting this call."
"Oh, you have, eh?" Detective-Lieutenant Barton grunted sarcastically. He glanced over Mortenson with shrewd, suspicious eyes and entered. Riley, his companion, followed him, his right hand buried in his coat pocket. Barton continued: "What made you expect this call?" he snapped bluntly.
At first glance at the newspaper headlines, Mortenson knew he would be suspected of being the phantom bandit. The world already knew that he, of all people in it, had been the first man to solve the mysteries of the Fifth Dimension through the use of strange apparatus such as worn by the bandit, but he had little doubt of establishing his innocence, so far as the robbery and killing was concerned. He sat down heavily in a chair as though to prepare himself for an ordeal of questioning.
"Well," he said slowly, "having invented the apparatus used by the bandit to make himself invisible, and being known as the inventor, I would naturally expect to be questioned by the law, considering the circumstances under which that apparatus has been used. I presume I am suspected of being the phantom bandit?"
Barton scowled as though taken aback by the scientist's cool, straightforward speech. He glanced at Riley, whose steel-blue eyes twinkled with suspicion and amusement.
"You are not only suspected, but accused, Mortenson!" Barton growled. "What have you to say to that?"
The scientist appraised him calmly, a flush of warm blood mounting to his cheeks. His head throbbed again and made him slightly dizzy.
"I'll say that I can put you on the right track if you'll listen and don't go off half-cocked," he said curtly, beginning to resent the officer's hostile attitude.
"I suppose you'll deny your guilt?" Riley put in ruthlessly.