However, as the man moved swiftly to the nearest telephone booth, suspicion began to take root. In identifying underworld characters, photographs were never a certain guide, that Penny knew. Too often a criminal disguised his appearance. Not by false wigs and beards which even a novice detective might note at a glance. Rather by altering his features or by adopting costumes commonly seen upon the street. Impulsively, Penny stepped into a telephone booth adjoining the one which the workman had entered. By leaning close to the wooden panel, she could hear part of the conversation. "That you, Jake?" he asked gruffly. "Everything's set for the big haul. We're all ready to go ahead whenever the boss gives the word." By this time Penny was almost certain that she was listening to the voice of Rap Molberg. Although in general the man did not resemble the photo which she had seen, the color of his eyes and the expression of his mouth were identical. His build seemed to correspond to the figures of the Bertillon record. A minute later the man slammed down the telephone receiver and left the booth. Penny waited until he was out of the store, then dropped a nickle in the slot. She called the number which her father had given her. There was no response at the other end of the line. "I suppose he's left the office," she thought frantically. "Oh, I can't let that man get away." She rushed from the drug store and reached the street just in time to see the workman disappear around a corner. "I wonder if I dare attempt to shadow him?" Penny debated. She was a little afraid, yet the streets in the immediate vicinity of the theater were well lighted, and it did not seem too dangerous. Turning the corner, she caught sight of the man far ahead. He was walking rapidly. She too quickened her step, but took care not to approach close enough to arouse his suspicion. Presently the man paused beside a fine looking automobile which had been parked at the curbing. As he glanced sharply up and down the street, Penny pretended to be looking into the window of a jewelry store. Actually, she was watching the man's reflection in the glass. She saw him step into the car, take a key from his pocket and turn on the ignition. As he drove away, Penny quickly noted down the license number. She glanced hopefully up the street but there was no policeman within sight. A taxi cab driver noticing her agitated expression, cruised close to the curb. Penny hailed him. "Follow that green car ahead," she directed tersely, climbing in. "Don't let it get out of your sight." At the first corner they were held up by a light which was changing from caution yellow to red. Risking arrest, the taxi driver crashed it. The green car ahead had picked up speed. It weaved in and out of traffic in a dangerous manner, driven by a man who was both skillful and reckless.