|Portrayed by:||Sendhil Ramamurthy|
|First appearance:||Any Means Possible|
Gabriel "Gabe" Lowen ia a former Artificial Evolved Human and an Assistant District Attorney that appeared for the first time in episode 15 of Season 1 as an attorney determined to investigate a strange death that may be linked to Vincent.
He is the ex-boyfriend of the late Tyler.
Gabriel was experimented on as a child by Muirfield when he was approximately four or five years old, undergoing genetic mutations that caused him to become a "first generation" human/animal hybrid. The experiments left him with Cross-Species DNA, similar, though not identical, to that of Vincent Keller. With the help of medication, synthesized by his Muirfield doctor, Vanessa Chandler, Gabe was able to fight his transformations and remain in human form. Without the medication, he remains in beast form, unconscious of his actions and unable to control them. Gabe was smuggled out of Murfield by Vanessa after she injected him with a substance that slowed his heart rate, mimicking the appearance of death. He was then adopted, and went on to become well-educated and successful.
Gabriel's success as an Assistant District Attorney leads him to the precinct of Catherine Chandler. He becomes involved in cases involving the vigilante, believing they are being mishandled, and presses the entire precinct for information, causing Catherine to become suspicious of his intentions. In Playing With Fire, Gabriel reveals his knowledge of Muirfield to Cat and his desire to destroy the organization, leading them to team up. Catherine discovers a secret Muirfield location known as the Orchard, the "brain" and main file storage location of Muirfield. In an effort to protect Vincent's identity from Gabe, Catherine corrupts the files which Gabe asked her to send to him. Gabe begins to suspect that Catherine is hiding something.
On the anniversary of Catherine's mother's death, Catherine learns of the special relationship Gabe had with Vanessa, and they bond over the shared relationship, causing Vincent to become jealous. Vincent suspects Gabe's involvement in the shooting of the mayor when it is revealed he paid $25,000 to an unmarked account. However, this payment was to a private investigator to discover if Vanessa's body had ever been moved, as the gravestone is damaged. Gabe and Catherine are lead to believe that Catherine's mother may still be alive, and they go to the return address of the release forms which were used to move Vanessa's body. At this abandoned house, the sniper who shot the mayor appears to kill Gabe, confirming that Gabe was the actual intended victim of the shooting. Vincent intervenes, and Gabe and Catherine escape with their lives. They discover Vanessa's true grave, and realize she is dead.Gabriel examines the crime scene of the abandoned home, and realizes that only the "beast" he had been looking for could have caused such damage. Gabe's eyes turn yellow, like Vincent's, and it is revealed that he, too, has cross-species DNA.
In Date Night, Gabe is placed in a hotel in order to keep him secure after the shooting. Gabe reveals himself as a beast to Catherine and informs her that he wants to give Vincent his medication in exchange for Vincent's DNA. Vincent agrees and when Gabriel learns Vincent has to die in order to get enough blood, Gabriel agrees by saying "whatever it takes". In Never Turn Back, Gabriel and Tyler make a plan to kill Vincent despite Gabe's confliction about it. After J.T. discovers their plan, Gabe takes Catherine hostage to force Vincent to get him to supply his DNA. Vincent takes Tyler, trying to persuade Gabe to let Catherine go. Although he clearly cares about her, Gabe tells Vincent to go ahead and kill her. Gabe tells Catherine about his childhood and how he lost control of beast side and killed his mother, with his father dying not long after. Gabe begins to turn and locks Catherine in the room and gives her the key to protect her. He breaks down the door to find Catherine has escaped throught the window with Vincent. He goes after them and fights Vincent before a helicopter shows up and a sniper shoots Gabe.
After Catherine restarts Gabe's heart, they discover Gabe is no longer a beast. Feeling like he owes his life to Catherine, he decides to help her find Vincent in order to make amends.
After Joe is fired, the DEA puts Gabe in charge. He works with Tess to try and find Vincent in order to help Catherine; despite the fact that they think he is dangerous. Gabe calls J.T. and asks for his help to locate Catherine and Gabe goes to get her from Vincent’s house boat. After Vincent hurts Catherine, she only tells Gabe what happened and asks for his help to find out who is controlling Vincent. He accompanies Tess and Catherine to an art show in order to find out what Vincent is up to and watches Catherine and Vincent dance. Tess catches him staring and later at the precinct, she accuses him of having a crush on Catherine. Gabe deflects the question and walks away smiling.
Gabe goes to Vincent’s house to tell him about how he was able to become human again. Gabe wants to go after the serial arsonist in order to test the theory and after Vincent attempts to catch him, Gabe goes to the hospital to see him with Catherine.Tess brings up Gabe’s feelings for Catherine and he says they are irrelevant because he owes her. Gabe helps Catherine look for her birth father. He and Tess go to Catherine’s high school reunion in order to warn her about Zack. When Vincent goes to get Catherine out of there, Gabe offers to do the same and they momentarily fight over her. Gabe tells Vincent that he’ll keep an eye on Catherine and he goes to see her in the gym. She thanks him for everything he has done to help her and they look through high school photos of Catherine before finding one that hints at Reynolds being her father.
Gabe suspects that Vincent’s last mission will end with Vincent dying, so he asks Tess to help find Vincent’s handler. Gabe suggests they try the defibrillator on Windsor, but the plan fails.