J.J. LaRoche became the new head of CBI Internal Affairs following Todd Johnson's murder by fire while in a holding cell. He also took over for Madeleine Hightower as CBI chief when she went on the run (after being framed for Johnson's murder). LaRoche came onto the scene after Johnson's death to find out who the perpetrator was. He wrote the suspect list for who Red John's CBI mole was - the man who really killed Todd Johnson. This led him to be one of the suspects himself because he could have forged the list. But he could have been proven innocent afterwards because Patrick Jane figured out that Craig O'Laughlin was the real mole. LaRoche is often in an antagonistic position to Patrick Jane most likely due to the fact he doesn't respect Jane's ability in solving cases. In Little Red Book he returns to the professional crimes unit and gives Teresa Lisbon an awkward hug stating that "working with Jane has been interesting." In Behind the Red Curtain he pretends to be the leading investor Burt Hannover (at Jane's instigation) to flush out the killer. He was killed in sixth season episode Black Helicopters by a booby-trap when helping Rigsby and Van Pelt investigate who is targeting former CBI members.
LaRoche was introduced at a briefing Hightower gave to the CBI after the murder of Todd Johnson (Jolly Red Elf). He later speaks to Jane outside of the holding cell where Johnson was killed. Jane and LaRoche had a conversation about a green lighter found in the room. Jane asked LaRoche if he could take a look at it, but LaRoche rejected it. The two, while they talked, were sizing each other up.
They later speak outside of an AA meeting that Jane went to so that he could get a better idea of the victim in their current case. LaRoche had followed Jane there, wanting to ask him questions despite Lisbon not wanting him to. LaRoche asks Jane about the secret Johnson wanted to tell him. Jane never told LaRoche, leaving the investigator to be more and more curious about Mr. Jane and his involvement with Johnson.
LaRoche began to take an interest in Rigsby. He knew that he was a former arson investigator, so he would be familiar with fire. He began to question Rigsby, who denied everything. LaRoche then brings up Rigsby's father, who has a rap sheet and a history with a motorcycle gang. In 2008, Rigsby helped his father out by providing an alibi after he violated his parole. That would have been fine if Rigsby didn't claim that Cho was there with them. Rigsby confronts Cho after he gets a call from LaRoche. Cho is very angry with Rigsby, saying he won't lie. But in the end he says he was there with Rigsby and his father. (Bloodsport)
After Van Pelt had been knocked out and an intruder had come into the house of a key witness she was protecting, LaRoche feels the need to talk to her about Johnson. At first he asks her about last night, asking if she did or did not lock the door behind her. Van Pelt doesn't remember. Then LaRoche springs on her the Todd Johnson investigation. He demands an accident report and a urine sample to test for drugs.
LaRoche tries to peg Van Pelt for a guilty conscience because of the locked or unlocked door. He offers her a chance to prove she is a good cop by becoming a spy in the CBI to find out who killed Johnson. Van Pelt does not want to wear a wire. She is very offended. Later she goes to talk to him, finding out the truth that she did indeed lock the door and the detective who had broken into the house also had a key. She then says that she is not going to be a mole because she doesn't want anyone to hear the private conversations she has with her friends and colleagues. LaRoche reminds her that someone within the CBI killed a man, someone she may trust. But Van Pelt still refuses. (Blood for Blood)
LaRoche confronts Hightower about the Todd Johnson case, informing her of a rumor that she was involved with one of his victims - Rance Howard. He says it would be a nice motive for her to kill Johnson, revenge. Hightower is becoming stressed over LaRoche, smoking in the parking garage, where she runs into Jane whom she's been avoiding. Jane tells her she has that look about her that says she's "been LaRoched."
Hightower and Jane later come up with this plan for Hightower to escape, duct-taping her hand to a rifle that is also taped to the back of Jane's head via duct tape around his neck. He appears to drive both of them out of the CBI parking lot, he in the driver's seat, Hightower in the back seat obscured by the dark glass window. Then chase begins, CBI and police not far behind, Soon after, Jane crashes into a metal bar, presumably to stop Hightower. When agents arrive, there is no one in the back seat.The long-barreled gun is propped there, the barrel still attached to Jane's head, and Hightower has fled. Lisbon, her team, Gale Bertram, and LaRoche set up a perimeter, trying to find Hightower. During that time, Bertram quotes William Blake. Not "Tyger, Tyger,", but "A Cradle Song" -- the last two lines: "And when thy little heart doth wake / then the dreadful night shall break" which LaRoche tells a puzzled Lisbon is William Blake. LaRoche then returns to his car to head home.
Jane takes a bottle of scotch to LaRoche as a thank you, then sneaks to LaRoche's car where Hightower is hidden in the trunk (Red Queen) -- the place she has been per her and Jane's plan (which is shown in a brief flashback) -- and Jane helps her escape unbeknownst to LaRoche.
When Lisbon and the team are investigating a dead doctor at a golfing range, LaRoche shows up to ask Lisbon about whether she knows anything about Hightower's whereabouts. Lisbon is pretty annoyed with LaRoche, claiming she is going to have him banned when Hightower is replaced. Unfortunately for her, LaRoche was appointed to take Hightower's position that morning and puts Cho in charge of the team.
At the end of the episode, Lisbon and the team arrest the murderer of the doctor. LaRoche congratulates Lisbon personally and reinstates her as the boss. He tells her, "Maybe I was messing with you." (Bloodstream)
LaRoche's house is broken into by some man, who has pulled out books from a shelf and is getting into the safe. LaRoche, holding a dog in one arm and a gun in the other, pops out. The intruder runs away, but the cops catch him. As he is being arrested, we see Jane's car speeding away. Jane manages to see the intruder, who is Donny Culpepper from the episode A Price Above Rubies. Jane had hired Culpepper to steal something from LaRoche. Culpepper threatens Jane, saying if Jane does not get him out free and clear, he's going to reveal all.
Jane eventually tells Lisbon why he hired Culpepper - to get the list of suspects for the Todd Johnson case. There are four people left on the list, besides Hightower. Jane claims that if none of the four are Red John's mole, then in must be LaRoche himself. Lisbon agrees to help Jane by punching Culpepper, which releases the man. No case. LaRoche is not happy and Lisbon has a week of suspension and has to attend anger management classes. Meanwhile, LaRoche has a call from the state department concerning his case. (Redacted)
The CBI are investigating a bombing that occurred at a gas station. They find some kind of code written on a bathroom wall that leads them to this locker room in Windsor High School. Jane goes to met Lisbon there, finding her strapped into a bomb vest, just like the first victim in the gas station, Dinkler. The bomber calls Lisbon on the phone and tells her to deliver CDs they recovered to him. Jane has of course figured out who the bomber is and instead of going to the evidence in CBI, they go straight to the bomber - the gas station attendant. (Strawberries and Cream)
Lisbon gets the vest off of her. The CBI shows up and LaRoche puts the guy into the car to arrest him. Suddenly, gunshots go off in the car and LaRoche has a gun in his hand. The attendant had tried to pick the lock on the cuffs and reached for the gun. LaRoche shot in self defense.
After running the client list on the CDs, the CBI get a name - Max James. Cho and Rigsby find him dead in his home. Along with a dead body, they find a picture of James with Hightower. Jane goes to his hotel which he sometimes lives in. Hightower is there. She admits that James was her cousin who had been sending her money. Jane wants forty-eight hours to find Red John before Hightower turns herself in.
Jane comes clean with the team - "Tyger, Tyger" references, the list of suspects, and how one of the suspects, including LaRoche, is Red John's mole. The team is in, ready to work the case. Jane makes a deal with LaRoche: Hightower for the suspect list. Jane threatens to reveal LaRoche's secret if he doesn't, and how Culpepper found a Tupperware container in the safe. LaRoche hands over the list immediately.
- Brenda Shettrick, the CBI's media relations manager
- Oscar Ardiles, Assistant District Attorney
- Gale Bertram, Director of the CBI
- Craig O'Laughlin, the FBI's liaison at the CBI
LaRoche returned in season 5, episode 4 Blood Feud. He was in charge of the internal investigation into Rigsby's actions which resulted in the killing of the man who killed his father, and an ex-gang member. In his report, LaRoche wrote that Rigsby acted appropriately in the situation. Although, he ultimately suspected that Jane had planned the killer's death at the hands of Rigsby.
LaRoche returned in season 5, episode 18, Behind The Red Curtain. In this episode, Jane requested his help in catching a killer by having him dress up as the murderer's alter-ego. This threw the killer over the edge and caused him to accidentally reveal himself.
He returned in the season's penultimate episode Red and Itchy. Executive producer Tom Szentgyorgi said in an interview "The mystery of what LaRoche has in the Tupperware container in his safe will finally be answered." It was implied at the end of the episode that the Tupperware container contained the severed tongue of LaRoche's mother's rapist. LaRoche reappeared in season 6 episode 13, Black Helicopters . At the end of the episode, LaRoche and Rigsby were investigating a darkened room when LaRoche set off a trip-wire with a shotgun. LaRoche was shot and died moments later. In season 6 episode 15, it was revealed that his murderers were Richard Haibach (ringleader) and Hazel Haibach (accomplice). Hazel was arrested and Richard was shot and killed by Rigsby.
- He speaks with a monotone voice and displays unfocused eye movements when speaking, because Pruitt Taylor Vince (the actor who portrays him) is diagnosed with pathologic nystagmus, (a condition which causes a person's eyes to move involuntarily).
- He has a small pet dog, similar to a toy poodle, actually of Maltese breed. His last words to Wayne Rigsby, prior to dying, are "My... dog."
- J.J. is notoriously known for his use of mind games when it comes to obtaining information and eliciting confessions from suspects (this is very clear in the episode of the third season, "Red Queen", when he managed to bewilder and destabilize Madeleine Hightower to get information about the case involving the brutal murder of the notorious serial killer Todd Johnson, occurred inside the CBI Headquarters and that Madaleine was one of the main suspects, since she is having a secret and forbidden relationship with one of Todd's victims, Officer Rance Howard).