Atrika

 was a Tibari scientist who employed Xantha soldiers which captured the Second Doctor, Jamie McCrimmon and Zoe Heriot. He wanted the Doctor and Zoe, as higher intellects, to experiment on using his mind projector, which utilised a Dalek crystal. He wanted to use Zoe to assassinate the Tibari president. When the Daleks took over the operation, he betrayed the Daleks by telling the Tibari about the assassination attempted. He was killed by them. (AUDIO: Fear of the Daleks)