|Minor Character: Las Vegas|
|Family||Amy McCarthy (daughter; deceased)|
|Portrayed By||Len Cariou|
|First Appearance||Law of Gravity|
Frank McCarthy was a dirty cop and molester who appeared in the Season Seven episode Law of Gravity.
Frank was a cop with Trenton PD and had a daughter named Amy. He was partnered with Dennis Graves and they eventually met a man named Michael Keppler. Michael was going out with his daughter Amy and the two eventaully got engaged. Then for unknown reasons, in 1985 Frank raped his own daughter, who later committed suicide, and blamed it on a man named Alvarez. Frank was going to kill him but Mike got to him first and executed him and gave the gun to Frank. Later Frank and Mike bonded over the grief of losing Amy and Frank used the money he was saving for Amy's future to give Michael a career in law enforcement. They would later help Dennis Graves when he would kill suspects in his cases and they would cover it up. Mike then left Trenton and left Frank and Dennis to carry out their work. Later Dennis was indicted for the murders and Frank got worried. He hatched a plan to take him to Vegas so that Mike could kill him.
Law of Gravity
Frank and Mike met at a local diner where he tried to solicit him a favor but was stopped by Mike before he could explain. So Frank instead solicited two prostitutes, one for him and the other for Dennis. He then went into Dennis' room and shot him at point blank range. The hooker he was with tried to escape but was shot by Frank and scratched him in the process, leaving his DNA under her fingernails. He cut off her hand to get rid of the evidence and took it with him. Little did he know that their was a witness to the crime, his hooker who bolted afterwards. Afterwards he blackmailed Mike into covering up his crime and to find that hooker. In the process Mike found out Frank raped Amy and set a trap for him. He held him at gunpoint with Suzy behind him where he confronted him on what Frank did. In the process Suzy escaped and Frank tried to kill her but Mike saved her and Catherine barges in where Frank tried to shot her but was shot and killed by Mike while leaving his colleagues the evidence needed to prove Frank was a murderer.
- Amy McCarthy (his daughter; raped and later committed suicide)
- Dennis Graves (shot once in the chest)
- Courtney Evans (shot twice in the back and left hand is severed post-mortem)
- Suzy Gibbons (attempted to kill; was rescued by Michael Keppler)
- Michael Keppler (jumped in front of Suzy to rescue her and was killed in the process)
- Catherine Willows (attempted to shoot, but he was shot dead by Mike)