Ellen Woodworth worked for C19.
When she met the Seventh Doctor in 1983, she pretended to be a ghost hunter. After Ia Jareshth and two Caxtarids were captured by the military, she chose to learn more about them through dissection rather than interrogation. Chris Cwej was her next subject, but the Doctor rescued him before he suffered the same fate as her other prisoners.
Realising he could not reason with her due to her obsession with alien invasion, he let Isaac Summerfield take her back to Little Caldwell to be dealt with. She managed to escape, but was killed by Ogri masquerading as a tombstone in a cemetery. (PROSE: Return of the Living Dad)