"We've been talking about this for YEARS! And now you're just gonna bail on me for some bitch?!"
Turner was formerly a resident of Lubbock, Texas. When he was sixteen, he raped a fifteen-year-old girl and made her twelve-year-old brother watch him commit the act before attacking the boy and causing great bodily injury to him. He was sentenced to nine years, the first two in juvenile detention and the remaining seven at Texas State Prison. During his incarceration in Texas State Prison, Turner shared a cell block with Benjamin Wade and William Duke Mason, who were imprisoned since 2010 for a robbery at an El Paso gas station where the clerk was killed. He became extremely close with Mason after he saved him from being shanked by another inmate and was implied to have developed homosexual feelings for him. They talked about opening a motorcycle shop together in Mexico after being released from prison. Turner was released from prison in 2014, followed by Mason one month prior to "Outlaw". The two then decided to commit a crime spree based on the one Mason planned to follow with Wade before their arrest.
After Mason and Turner commit a robbery at Dee's Original Diner, they take the three night-shift employees hostage and kill them. They leave the place on their motorcycles just as the place is set on fire. Turner and Mason settle in a motel for the night. The next morning, while Mason counts the stolen money, Turner inhales drugs purchased with the money. When Mason leaves the motel to see Tammy, Turner goes to the local pharmacy and takes Randy McAdams, the pharmacist, and his niece Jane, the cashier, hostage. He picks up some pharmaceutical drugs and injects himself with them. Then, he kills Jane in front of Randy before killing him as well. When Turner returns to the motel, Mason asks him where he has been, and he replies that he went out to the pharmacy. Realizing what he had done, Mason becomes enraged, but Turner shakes off his response, adding that he was expecting Mason to thank him. They both leave town and stop by at a gas station. After the clerk holds Mason at gunpoint in self-defense, Turner steps inside and shoots him, then takes the money from the register while Mason shoots out the security cameras. Seconds later, Mason spots a boy and his father, who begs for their lives in Spanish. Turner spots them as well and tries to shoot them, but Mason convinces him to stop, as the boy reminds him of his own son.
Turner and Mason are next seen parking their motorcycles on the side of the road after fleeing the gas station. Turner furiously asks Mason why he didn't shoot the boy. Mason replies that he doesn't kill kids, but Turner tells him that the boy is a witness. He then asks Mason why he didn't shoot the father, and Mason answers that the boy needs his father. This causes Turner to realize Mason is having second thoughts about the crime spree and wonders if he has something planned without him. Mason confirms this, saying that it was time for the both of them to split up. Deducing the visit with Tammy had a factor in this development, Turner tells Mason about their plan and insults Tammy, calling her a "bitch", prompting Mason to punch him and leave him on the side of the road. Hours later, Turner come across Mason, Tammy, and their son Cole in a campground in the local woods. Turner introduces himself to Tammy, stating that he is Mason's partner. When Mason tells him to back off, the BAU and police show up. Not wanting to go back to jail, Turner engages them in a gunfight along with Mason. He is eventually shot once by Chief Raul Montoya with a sniper rifle, telling Mason "He got me good" before dying.
During his robbing and killing spree, Turner operated with Mason in all of his crimes except for the one at the pharmacy. During the Dee's Original Diner robbery, he emulated Mason and Wade's original robbery at the Burger Corral, restraining the night staff (all teenagers) right after closing hours (the males were tied up with their own belts and electrical wires, while Renee Acosta was tied up with her own underwear), raping Renee, and killing them with single gunshot wounds to the head fired by a handgun. He then stole the money from the register and the safe and set fire to the restaurant and the victims' bodies as a forensic countermeasure. The only distinction from the original crime was that he forced the victims to watch each other be killed by him while seated as a form of psychological torture, which was a signature for most of his crimes.
During his solo robbery and killings at the pharmacy, he forced Jane McAdams to watch him shoot her uncle Randy, but didn't rape her. He also didn't set the pharmacy on fire as a forensic countermeasure. Also, besides stealing the money from the register, he stole methamphetamine hydrochloride, some of which he injected himself with before killing the pharmacy staff and taking the remainder to share with Mason.
Turner has some similarities to Kenneth McDuff, a serial killer infamous for being paroled despite initially being sentenced to death for a brutal triple homicide, whereupon he began killing again. Like McDuff, Turner was a Texan who killed three teenagers (two males and one female who was also raped) in one event, with the help of an accomplice. Both also tortured their victims in some way and later moved to another state, though McDuff didn't continue his killings there. In addition, McDuff was an early suspect in a 1991 mass murder at an Austin yogurt shop, the event that was the apparent inspiration behind the 2009 mass murder at Burger Corral committed by Mason and Wade.
- Turner shares some similarities to Henry Frost, a budding serial killer who appeared in Season Three. Both were members of two-person killing teams who eventually developed homosexual feelings for their partners (although in Turner's case, it was only implied, and he was dominant alongside his own partner whereas Frost was submissive to Francis Goehring), and who died in similar standoffs with the BAU, in which they attempted to kill at least one member of the team but were shot to death by an officer with a sniper rifle in Rossi's presence.