Lt. Debra Hughes

Lt. Debra Hughes is the main antagonist from "The Fallen," episode 14.19 of CSI.

She was played by Scottie Thompson, who also played another CSI franchise villainess, Lia Ramsey, on the NY series.

History
Debra Hughes is a lieutenant with the LVPD, as well as the wife of one of her subordinate officers, Blake Hughes. She was first shown informing D.B. Russell regarding Jacob Baker, a teen criminal who blew up a politician's BMW before encountering her husband and sending him to the receptionist's desk. Shortly afterwards, a teenage gunman, identified as 16-year-old Mark Powell, enters LVPD and shoots Blake in the chest, after which he fired more shots before taking Russell hostage.

In the process, Mark shot and killed another officer, Kenneth Matsuda, and regarding Debra, she approached Jim Brass regarding Blake, who was hospitalized due to the shooting. She appeared again at the hospital and was encountered by Sara Sidle, which saw Debra reveal that there had been marital problems in the past, but she claimed that things were better between the two; however, Debra was informed later on that Blake succumbed to the shooting, leaving Debra in grief.

Reveal
An investigation into the shooting revealed that Mark had an accomplice, as it was uncovered that he had been in contact via email with someone known as "Lookingglass419," who spoke out against the police and coerced him into shooting up LVPD. A search into the email communication led to a shocking reveal by Julie Finlay:  Mark's accomplice was a police officer. While Mark was in the midst of giving himself up, Greg Sanders and Morgan Brody searched all of the officers' laptops, using process of elimination to pinpoint which one was used to communicate with Mark, who was later killed when he reached inside his vest. It was officer Robert Dolan who gave the order thinking he was reaching for a gun, but it was actually his St. Christopher's medal.

Regarding Dolan, it was his laptop that was revealed as the one used to communicate with Mark, resulting in Dolan's arrest--much to his bewilderment. However, Sara informed Debra about Dolan's arrest and stated that not only did she not believe that Dolan was the culprit, she knew who the true mastermind was:  Debra. As it turned out, Debra was having an affair with Dolan, though Debra claimed that Dolan was upset over her breaking it off to remain with Blake. Sara revealed that Debra knew Mark back when he participated in the Police Youth Sports camp a year prior, as she showed Debra a photo of the two of them together. Debra turned heel later on by manipulating Mark into killing her husband, doing so by sending emails to him posing as Lookingglass419, a person who hated police, and even giving Mark the go-ahead to start shooting just two minutes after she sent Blake to the receptionist's desk.

Debra's villainous actions resulted in the death of not only her husband, but another fellow officer, as well as Mark himself, leading to Sara lashing out at the villainess for her actions and asking for a reason why. After much denial, the evil Debra gave a list of teased reasons before stating that nothing she said could make Sara understand the reasons for her actions. A pair of officers appeared and arrested Debra, after the fiendish villainess asked for her police rep.