The reason why Jezek was imprisoned on SAR TOP prison was never revealed in the episode - nor what he was doing when he came to Earth. Following his defeat of the Vardian called Zin (who had masterminded the escape) and his hiding of the dangerous Strada Brac, Cole/Daggon continued his hunt for the remaining fugitives. Seeking a way to capture all the remaining prisoners at once, Cole masterminded a possible way to accomplish this - but needed a test subject in order to ensure it would work. Soon enough, Cole was on his next hunt; Jezek been his new target.