Brad Alcerro is Harvey Kinkle's old best friend who moves back to Westbridge in the show's fourth season after living in Texas. Not much is known about Brad's life except for the fact that he has a step-father. Brad is revealed to have a witch hunting gene, which makes his presence at Westbridge High a threat to Sabrina.
Brad initially dislikes Sabrina, seemingly for no reason, until it is revealed by Hilda and Zelda that he is a Witch Hunter. Brad doesn't know what he is, though whenever he is around a witch or magic is used in his presence, he senses it and immediately becomes cautious, which is why he is constantly rude to Sabrina.
In the episode "Dreama, the Mouse," after Sabrina's tutee, Dreama uses magic in front of him, Brad declares his thinking that she is a witch which turns her into a mouse. Sabrina and her aunts then try to remove Brad's witch hunter gene or else Dreama will be stuck as a mouse for 100 years.
They are successful despite the fact that Sabrina had Spring Fever, and remove the gene, which is literally a pair of tiny blue jeans. Afterwards, Sabrina and Dreama are both free to use magic around him like they would any other mortal. Despite eventually losing the gene, he still remains a jerk to Sabrina and Dreama.
After the fourth season, Brad was one of several high school characters never seen or mentioned again. Presumably, he went off to college, away from Westbridge.
- Witch hunting gene: Brad is mortal but was born with a special witch hunting gene that grants him a number of abilities but he does not have conscious control.
- Magic Sensing: Brad's witch hunting powers mean he can sense the use of magic and can also instinctively sense witches when nearby.
- Transfiguaration: If Brad successfully accuses a witch of being one, he can unconsciously transfigure them into a mouse for 100 years.
- Weather: The Earth's atmosphere affects the witch hunter gene through atmospheric pressure, temperature and humidity so in the right weather his gene is disabled.
- Loss of Memory: When the witch hunter gene is disabled he loses all memory of magic meaning if a witch is in imminent danger, another witch out of sight can change the weather to erase his memory saving the threatened witch.
- Brad is the main antagonist of the fourth season, a role fulfilled by Libby Chessler in seasons one through three. In his first episode appearance, Sabrina even comments: "Okay, if he calls me a freak, I know Libby got hold of some male hormones." She says this after trying to befriend him, unsuccessfully.