Professor Mis'Kin Karac was a chronal physicist researching quantum flux technology, using genetic labels as guides. He developed a gun which would fire bullets that would remain intangible until hitting its genetically-tagged target, thus obviating the need for a clear shot. Karac's assistant killed him with the gun, then framed Peri Brown for the crime. However, the Sixth Doctor was able to make the assistant confess at Peri's murder trial. (COMIC: The Forgotten)