Glenda Yarnell (Deborah Winstead) was a villainess from Matlock’s eighth season opener, "The Play," (airdate September 23, 1993). She is a bank manager and a participant of a community play, which also had Ben Matlock, Cliff Lewis, and Leanne McIntyre as cast members.
As revealed later on, Glenda was an adulteress as well as a blackmailer, as she was engaging in an affair with the play’s married director, Doug Michaels. It began as a one-night tryst, but Glenda became obsessed with Michaels and forced him to continue seeing her, threatening to tell his wife if he didn’t comply.
Glenda was also blackmailing fellow cast member Jane Dryden, who also worked at the bank as a teller. Jane was originally a loan officer, but she was demoted to teller by Glenda, who did so after learning that Jane was embezzling money from the bank; instead of reporting Jane, however, the evil Glenda blackmailed Jane into doing various odd jobs for her, in exchange for her silence.
Glenda’s villainous persona was shown early in the episode when she encountered Michaels and accused him of making a pass at Jane, while hinting at their affair and threatening to tell his wife. Later on, Glenda was in her dressing room putting on her contact lenses, when she was suddenly strangled to death by the evidently equally evil Jane.