Charlie McWenstle is an arson investigator on Beauty & the Beast. He was portrayed by Joel Keller.
Charlie is first introduced when Vincent Keller is found unconscious at the scene of an arson, and admitted to the hospital. Charlie shows up with Aaron, hoping to find out about the arsonist who set the fire. Vincent is introduced to Charlie and Aaron as "Victor," an undercover officer, by Gabriel Lowan and Catherine Chandler. Gabe stonewalls them, saying "Victor" can't remember what happened. When Aaron becomes angry and demands answers, Charlie gets him to calm down. He then reveals that Aaron's last name is Keller, and Vincent, Catherine, and Gabe realize Aaron is Vincent's nephew. Gabe has Charlie & Aaron leave after this in order to protect Vincent.
Vincent & Catherine go meet Charlie & Aaron later, trying to help them find the arsonist. With Vincent's help, they figure out where the arsonist is going to strike next. Aaron tries to take off prematurely, but Charlie stops him. However, when they get word of a fire at the arsonist's targeted building, Charlie, Vincent, & Catherine realize Aaron has taken off by himself. Charlie desperately tries to find Aaron at the building fire; fortunately, Vincent goes in and is able to rescue Aaron. He brings Aaron outside, and alerts Charlie, who immediately brings paramedics to help Aaron, while Vincent disappears.
- Charlie looks after Aaron like a father, making sure he stays out of trouble.
- Charlie implies that he also knew Vincent's other brothers, Daniel and William, the latter of whom is Aaron's father. He mentions them to be stubborn and looking to take action before thinking, and tries to prevent Aaron from doing the same thing so he won't get killed.