- "The government has no business experimenting with magic. Besides, the mayor might think magic is evil, but I’ve seen it do good as well. I can’t stand by and let the mayor harm good people."
- —Murphy to the Chosen.
Agent Murphy is a mortal federal agent working for Homeland Security. He was placed in San Francisco to monitor the Charmed Ones and later worked with them on several magical cases until the sisters broke ties with the government.
During the investigation of inspector Sheridan into the Halliwell sisters, Homeland Security arrived in the city and took over. After the sisters faked their deaths, the agent in charge, Keyes, decided to drop his investigation. However, he left agent Murphy behind to monitor the situation.
Murphy later followed Billie Jenkins and saw her using magic against Imps. He then confronted her and the sisters about several innocents being killed by the Imp Master and the demon Antosis. After the sisters decided they could no longer remain hidden, they revealed themselves to Murphy and he helped them regain their old identities by stating Homeland Security had faked their deaths.
The sisters later confronted Murphy when they discovered the government had created a virus killing magical beings due to a failed experiment. After finding a cure, Murphy and the sisters decided to end their relationship.
When Billie and her friends were investigating a pair of magical twins robbing banks, she called agent Murphy to get access to the crime scene. Murphy went with them and later sent Billie footage from the security cameras. After the Chosen confronted and defeated the twins, Murphy and Homeland Security surrounded them to arrest the twins. However, the Chosen then helped them escape to avoid the government getting their hands of magic again. Murphy warned Billie and her friends that he would bring them in as well though Billie replied that she and her friends were too powerful for him. Murphy then reluctantly left.
After San Francisco was trapped outside of time and space, Murphy worked with the mayor to contain the situation. He was nearly killed by Klea with her poison, but cured after the mayor agreed to her deal. After the Brotherhood was vanquished, the mayor asked him for help in ending the threat of magic in her city.
Murphy reappeared pursuing leads on Nick and Nathan and confronted Duncan and later Billie. Because of this and a demonic attack, Duncan and the twins appealed to the Tribunal, resulting in all evidence of their crimes being erased.
When the mayor revealed a new version of the magical virus to Murphy, he asked the Chosen for help to destroy it, as he didn't want good people to be affected by it. When seeing the twins, he remembered their crimes, though since all evidence was gone and there were more important things going on, he decided to let it go. Along with Billie and Duncan, Murphy broke into the laboratory to destroy the virus.
Once there, they fought with the demon Margoyle, allowing a scientist named Ramsey Tate to escape with the virus. They were later confronted by the mayor, who was disappointed with Murphy and said she was going to report his actions. After she left, Murphy went to inform Homeland Security of the threat of the virus.
- Charmed, Season 8, "Still Charmed and Kicking"
- Charmed, Season 8, "Rewitched"
- Charmed, Season 8, "The Lost Picture Show"
- Charmed, Season 8, "Hulkus Pocus"
- Chosen Chapter 6: The Gemini Factor
- Chosen Chapter 7: City of Darkness
- Chosen Chapter 10: Raiders of the Lost Valley
- Chosen Chapter 14: Past and Present Danger