"Every day I think about your touch, your smell. I wonder when we'll be back together again. Winter, summer, or fall, the metal bars that separate us are just temporary, Maggie. Instead of keeping us apart, they made us closer."
Thomas "Tommy" Brown is an incidental character who was the lover of spree killer and statutory rapist Margaret Hallman, being the father of her child.
Background
At the age of fourteen, Tommy was a student in Margaret's class. The two fell in love and started a secret romantic relationship, which resulted in Margaret becoming pregnant with his child. Tommy's mother caught on to the relationship, and as a result, Margaret ended up being arrested for molestation. She gave birth to their child while she was incarcerated and named him Johnny after her first lover (whom Tommy was unaware of), but the baby was put into foster care. Tommy's mother later had a restraining order put against Margaret, who would later be released in 2012 and subsequently commit a killing spree while in search for Johnny.
I Love You, Tommy Brown
Upon getting Johnny back, Margaret returns to Tommy's house with their child, and they instantly rekindle their old relationship. Later on, his neighbor, Julie, shows up to the house to ask him to a dance, which he tells her that he's not into dancing. Julie then hears the sound of a baby crying, and goes to investigate where she discovers Margaret and the baby. Margaret sends Tommy to the car and proceeds to berate Julie and non-fatally shoots her. Hearing the gunshot, Tommy asks Margaret if she shot Julie and says that she could die, to which Margaret tells him that he is the love of her life, and that if she's not the love of his, then he needs to get out of the car. He responds by telling her to drive. They arrive at Margaret's new house, where they profess their love for one another and he reads a love letter he wrote for her.
Later, the BAU and police, investigating Margaret's killings, show up at the house and she goes hysterical, pointing a gun at him and asking him if he called the cops. Tommy replies that he would never do that, and she tells him to prove it. She gives him the gun and tells him to protect his family. Tommy goes outside and tells the BAU to get back and to go away, telling them that he loves her. The BAU reiterate by telling him that there was another student from another school that Margaret loved before him and that she named their child after him. Tommy asks the nearby Margaret if that is true, but she denies it. However, he isn't convinced and drops the gun. Margaret rushes to pick it up and attempt to shoot Morgan and JJ, but gets shot by Hotch. A panicked Thomas rushes to her side and tells her to not leave him. She ends up calling him Johnny Lewis, the first student she molested. Though he didn't directly participate in Margaret's killing spree, he was presumably incarcerated or institutionalized for his actions at the house.