He has appeared in three episodes, Cowboy, The Return of Victor Larue, and the Trial of Victor Larue.
Larue is very sociopathic criminal that has plagued Alexandra "Alex" Cahill in all his appearances and has held a desire to kill Cordell Walker after being defeated by him. He also has a sick obsession with Alex to the point where he has almost a psychotic love for her.
It is revealed in the episode "Cowboy" that he was dishonorably discharged from the army for being "too ruthless with the missions". It is because of this that he seems to be able to hold his own when fighting Walker but he is always defeated in the end. He seemed to become more and more insane with every appearance but he is also very cunning, often exploiting bureaucracy to keep the rangers away from him. It is interesting to note that he is very similar to the Dirty Harry villains, Scorpio as he is seen paying a thug to beat him, using bureaucracy as weapon, killing/kidnapping people at random, is completely insane, has a malevolent disregard for children, hijacks a bus, and is shot at point blank range by the hero in the end. The only difference is that Larue has minions in his first appearance. Larue is arguably one of the most dangerous and evil villains on televison.
In his first appearence, he held several people, including Alex, hostage for a ransom demand. He and his thugs then took them back to a house with the rangers hot on his tail. His plan began to fall apart and he took them to several locations. At one point, he catches Alex trying to call Walker and tries to rape her. Walker stops this by screaming at Larue over the phone threatening to "rip his heart out" if he touches Alex. With the rangers chasing him, he and his men hijack a bus to throw them off. Walker retakes the bus, then shoots and interrogates one of Larue's men, who tells them where they are going. Walker eventually comfronts Larue in a junk yard and manages to knock him out and save the hostages.
The Return of Larue
In The Return of Larue, he is released from prison on a technicality and begins stalking Alex and taunting the rangers by: putting a dead rat on Alex and Walker's dinner plate at a restaurant, luring them into his apartment and scolding them for preforming an "illegal search", paying a thug to beat him, and showing up at Alex's court hearings claiming that he is a "law abiding citizen". He even attempts to move into Alex's apartment after destroying it and leaving death threats.
Alex stays with Walker but he finds Walker's ranch by breaking into her office and finding Walker's address in her Rolodex. He then ties her up in the guest bedroom. Walker then comes to check on her but is knocked out by Larue who drags him to the badlands, ties him up, and then delivers a insane monologue about seeing a small mouse get stung to death by scorpions. He then takes a jar full of scorpions and dumps them on Walker's chest before running back to the house. Walker is stung, but manages to escape with the help of his horse via a trick he taught it. He gets to LaRue before he can rape Alex, and after a long fight, kicks him out a window, knocking LaRue out. He is then sent back to prison, with Alex ensuring that he would never be able to get off on another technicality ever again.
Trial of Larue
In The Trial of Larue, Alex goes to court where he is deemed competent to stand trial despite what his lawyer said. After that, he goes crazy and dives under a table. When the bailiff tries to stop him, Victor grabs the bailiff's gun and kills both him and his own lawyer and knocks out the judge. He then held everyone hostage and convinces another criminal to be his "army". When the judge awakens, he murders her.
He makes a few demands including a bacon sandwich and have Walker come in so he can kill him. However, Walker was going after two criminals in the woods and didn't know about the situation. While he waited he took over as "judge" and listened to a custody hearing over two divorced parents deciding who should get their daughter. He decides to make the child choose and forces the two parents to get back together when the girl said she wanted to be with both.
When his bacon sandwich comes, he is disgusted that his bacon is not crispy and asks everyone if he said he wanted crispy. Because people were afraid, they all agreed except the child who mentioned he never said crispy. Angry at the kid, he "reopens" her custody hearing. Trivette, who was tied, mentions the child and asks Victor if he wants her to grow screwed up. Victor then implies he plans to kill the child.
The other criminal takes a disliking to Victor (implying that the criminal has standards), so he takes his gun and points it at Victor. Larue pleads with the criminal not to shoot; but the criminal fires the gun, only to learn it was empty. Victor gets another gun, and the criminal pleads with Victor, only to get shot and killed. Victor then tries to rape Alex, who tells him Walker will always be the better man. Walker then bursts in heroically and shoots Victor twice, finally killing him.
As his corpse is wheeled out, Alex has a vision of him getting up and looking at her.