Paula Cassidy was an NCIS Special Agent who was originally assigned to Guantanamo Bay as an interrogator.
She later returned to Washington D.C. before being reassigned to the Pentagon where she led her own team before she died in the line of duty in April 2007.
Not much is known about Cassidy's history but according to her file, she was born in an area of Canada.
She later emigrated to the United States, presumably gaining citizenship and ultimately joined NCIS.
NCIS Season 1Edit
Cassidy made her debut appearance in the NCIS Season 1 Episode 8, "Minimum Security". When a Translator she worked with, Sa'id, is killed and found with Emeralds inside his stomach, she is immediately seen as a suspect and possibly accomplice. She reveals that she suspected Sa'id was faking his translations with a certain prisoner, as their conversations seemed longer than what they translated to be. Sa'id, who had a copy of her room key, learned of her suspicions and fled.
Cassidy made these notes in her personal logs, and didn't make an official record. As a result, she is nearly responsible for a murder in Gitmo by the prisoner in question, however Gibbs and his team learn the truth and help to stop it. Because she allowed her personal feelings and friendship to cloud her judgment and didn't report her suspicion, Gibbs' opinion of her isn't good.
NCIS Season 2Edit
Cassidy reappears in Season 2 Episode 8, "Heart Break". By this point, she is serving as the Agent Afloat on the USS Kennedy. Gibbs and the team encounter her in search of Ensign Evan Hayes who is suspected of killing his C.O., as they had arguments and he's now disappeared. Cassidy recognises them, saying she had to step in when the Ensign verbally threatened his C.O. However, at the C.O.s request, Cassidy didn't write a Report of Investigation, breaking every rule of being an NCIS agent. She felt sorry for him as he didn't deserve the abuse.
The team soon learn that the C.O, Commander Dorian, served under Ensign Hayes father, Captain Hayes. Dornan was a young lieutenant who was 'put in his place' by the Captain, and this cruise was payback time.
Ensign Hayes is soon killed in a standoff with Agent Todd, who shoots him in self defence. However, they then learn that Hayes was innocent, as he lost his nerve on confronting the Commander. Gibbs comes down hard on Cassidy, saying that she chose not to file a report, now 2 navy officers were dead, and they'll never know if it would have mattered. Cassidy is angry with Gibbs, as she refuses to answer Tony's calls.
NCIS Season 3Edit
In the months following Kate's death, Cassidy served as a brief replacement on the main NCIS Major Case Response Team and she became DiNozzo's temporary partner. Season 3 Episode 3, "Mind Games". She is kidnapped by a psychopath trying to please a serial killer, but is found and rescued before she becomes his next victim.
NCIS Season 4Edit
Cassidy's final appearance came in the Season 4 episode, "Grace Period" where it was revealed that she worked out of the Pentagon, commanding a team of her own which was composed of herself and NCIS Special Agents James Nelson and Rick Hall.
Tragically, both Nelson and Hall were subsequently killed by a suicide bomber with their deaths greatly devastating Cassidy and also leaving her stricken with grief and regret. For most of the episode, Gibss and the team try to keep her at arms length from the investigation, but relent when she goes around them.
Cassidy sacrifices herself to save everyone from a suicide bomber, pushing him through a false wall and closing the access seconds before the bomb goes off, killing the bomber and her alone.
Paula Cassidy is an ambitious and intuitive woman, who can tell if people aren't being truthful. However, she ignores these feelings as she values friendships and doesn't want to raise unnecessary issues. This repeatedly brings her at odds with Gibbs, who on their first to encounters, had to clean up a mess she created by not doing her job properly. It is assumed she is demoted for this.
Cassidy was a short woman in her mid-thirties with blonde hair she later dyed brown and light blue eyes.
As an NCIS Special Agent, Cassidy was highly skilled in interrogating various suspects.