|“||That was my idea too...||”|
— Nelson to Ellen Russell and Darlene Beckett
Little is revealed about Nelson's early life or how he became a psychopath and a pedophile. Sometime in his adulthood, he started his series of rapes and murders, claiming the lives of at least four girls, including one Kelly Taylor, whose disappearance on March was pinned on Mark Logan, one of three friends who were with him at the time of the murder; Logan actually participated in sexually assaulting her, while the other two apparently watched them. After murdering Taylor, apparently without the knowledge of his friends, Nelson then disposed of her body. Logan took the fall for Taylor's disappearance and was sentenced to ten years in prison (since her body was never actually found at the time), which was spent being visited by Nelson and his other friends.
After killing both Mark Logan and Paul Montgomery, two of the other men who were involved in Kelly's murder, Ellen Russell and Darlene Beckett (the latter of whom was Taylor's mother), break into Nelson's apartment in the middle of the night and confront him. Feigning remorse, Nelson offers to take them to where Taylor's body is buried in exchange for his life. As the three of them drive to the burial site in Russell's SUV, Nelson reveals his true nature as he tells the women how Taylor suffered in detail, then reveals that he had been expecting someone to come for him ever since Logan and Montgomery were killed, and told his neighbor to write down the license plate numbers of any strange cars that showed up outside his place and report them to the police. Angered by his deception, Russell pulls over and throws Nelson out onto the pavement, intending to kill him, but is stopped by Beckett, who wants to find Taylor's body so she can have closure. Meanwhile, the BAU arrive at Nelson's apartment and find his trophy collection while searching for evidence. Reasoning that he would have moved Taylor's body after finding out his accomplices are dead, they examine Nelson's on-site storage unit and find a recently-used shovel. After the field agents identify the type of soil on the shovel's blade, an uncommon type for the area, Garcia is able to determine the location where Nelson had most likely reburied the remains.
Sometime later, Nelson tells Russell to pull over again. When they all get out of the car, he tells the women that he has decided that he won't take them to Kelly's burial site unless they kill a random person, explaining he wants Russell and Beckett to know how he felt the day he decided to kill Taylor and reminding them that the longer their trip takes, the better chance the police has of finding them. Against Beckett's objections, Russell opens fire on a passing motorist, causing his truck to careen off the road and down a nearby hill. As the group continues on to Taylor's burial site, Nelson taunts Russell, accusing her of secretly enjoying shooting at a stranger for no reason. He also tells her that they should team up and start killing across the country. Russell responds by threatening Nelson, saying that she will kill him if he doesn't lead them to Taylor's body soon. He eventually leads them to an open field at the base of a hill just off the road, claiming that he isn't sure exactly where Taylor's body is since he had moved it after his friends were killed. When he finally finds the right spot, Russell hands him a shovel and orders him to start digging. Eventually, Nelson unearths Taylor's skull. When Beckett asks him where the rest of Taylor's remains are, he tells her he had dismembered her body and buried it in different places all over the field, and says they will have a few more holes to dig to find the rest of her. Enraged, Beckett attacks Nelson, bludgeoning him to death with the shovel before she and Russell flee the scene. Nelson's body is later found by Rossi when the BAU arrive at the burial site.
"We've got a few more holes to dig"
Nelson targeted young girls, attacking them when they were isolated and raping them before killing them. Because the bodies weren't found until the end of the episode, it is never revealed exactly how he killed his victims, but since Nelson alleged to have dismembered Kelly Taylor's body, it is possible they died this way. After killing them, he took jewelry or small articles of clothing as a trophy.
"I want you to know how good I felt"
No official profile was made for Nelson, as the BAU were more focused on Russell and Beckett. However, when examining evidence found at his apartment, they concluded that he was a clinical psychopath, incapable of feeling empathy, but being able to fake it in order to blend in or buy him time.
Nelson's murder of Kelly Taylor is very similar to the murder case of Jon-Niece Jones - Both victims were underage African-American girls who were murdered in 2002 and had their bodies disposed of in wooded areas, remaining undiscovered for several years until their skulls were found, then the rest of their remains. Both cases also involved the killers having three accomplices who assisted them in the crimes in some way (one of Nelson's accomplices had directly assisted in Taylor's rape and the other two watched and stayed silent, while Elisha Jones's accomplices helped her dispose of Jon-Niece's body). On an unrelated note, the episode featuring Taylor's case, aired on October 2012, the same time when Jon-Niece was properly identified, and in addition, the episode aired on October 10, exactly one day after Likisha, James, and Godfrey's arrests.
- Unspecified dates: At least three unnamed girls
- March 2002: Kelly Taylor
- October 10, 2012: Unnamed male motorist (attempted, but barely survived; manipulated Russell into shooting him)