The Bloodhounds of Zirth

No one escaped from Zadda, Earth's grim penal star. The barriers were too steep. The Zirthan guards too clever. The mertha hounds too keen at trailing. Only 4W382ZT won free—though he couldn't beat the awful rap.
There was silence in the grim room broken only by the riffle of filing cards from the corner where a trusty, in gray uniform, sat working at a small desk. Warden Hughes sat at his large desk, idly fingering a small scale-model of a space ship which he used for a paperweight. Across the desk from him, in a stiff-backed, plastic-covered chair, sat Greg Purnell, special investigator for the Congress of Earth.
Before Purnell had time to speak a bell shrilled on the warden's desk. Hughes tabled the paperweight and picked up the phone. Purnell could not tell from any change of expression what the message might be. The warden listened carefully, grunted an uninforming Yes, and then? into the phone, listened some more, and finally hung up. Immediately he lifted it again and dialed a number.
Send Rol, Dorta, and two mertha to my office at once. Have the helicopter ready to go in ten minutes.... What?... Then have two zerda saddled and ready. Hop to it.
Purnell nodded but the warden had already turned his back and was punching out a code on the panel behind his desk. He had scarcely finished when there was a sigh and a ting. He slid a panel aside and took a flat spool out of the cavity behind it. He placed it carefully in a squat machine which stood beside his desk.
There was evidently nothing more to be done until the arrival of Rol, Dorta, and the two mertha, for the warden settled back in his chair and turned toward Greg.
That spool is the mentape of 4W382ZT, the prisoner who escaped. You'll see what it's used for in a minute or so.
There was a firm tap at the warden's door. Purnell mentally chalked up a note to commend Hughes for efficiency when he sent in his report. The warden touched a button on his desk and the door swung open violently, pushed aside by two creatures which bounded into the room.