|“||He was always breaking my stuff. I'm not going to miss that.||”|
— Danny about Kyle
Born sometime in 2000, Danny was a boy with an affinity for building model planes, and tendencies of rage. Danny lived in Cherry Hill, New Jersey with his parents and younger brother, Kyle, whom Danny absolutely loathed due to him being "a baby" and because of his habit of breaking his toys. Possessing an explosive temper, Danny once killed a puppy that his parents brought home for no reason. One night on April 20, 2009, while up in the middle of the night working on one of his planes (a World War II-era B-25 Mitchell bomber) Danny was found by Kyle, who told him their parents would be mad if they found him up this late. When Kyle then asked to see his new plane, Danny told him he could look at it but not touch it. While gone for only a few seconds, Danny returned to find that Kyle had accidentally smashed the plane and, in a fit of rage, killed his brother by stuffing the broken plane pieces down his throat.
Discovering what he had done, Danny's parents, Dan and Sarah, having just lost one son and finding the thought of the other being taken away unbearable, made it look Kyle was the latest victim of a murderous pedophile named Hugh Rollins, who had been abducting, raping, and murdering young boys in the area. Their friend, Detective Bill Lancaster, helped out with the plan. Too preoccupied with Kyle's death and trying to cover it up, Sarah, Dan, and Bill failed to notice how disturbingly nonchalant Danny was throughout the entire affair, rationalizing he simply did not understand what was going on when the boy's odd behavior is noticed.
A Shade of Gray
"I told you not to touch it! You never listen!"
When Danny was younger and Kyle was extremely young, his parents bought him a puppy, which Danny killed for absolutely no reason, apart from the fact it may have slightly annoyed him, however, his sociopathic tendencies had no threshold for minor errors which every living thing does, including humans. He may have also gained pleasure from the act and calmed his surging rage.
News of Kyle's disappearance eventually reaches the media, and the BAU is subsequently called in to help investigate it and the other abductions. Danny appears on a televised plea made by his parents for their son's safe return. When Prentiss questions the family, she asks Danny if anyone suspicious has been around and tries to talk to either him or Kyle; Danny answers with a no before asking his father if he can go play, which Dan allows. The pedophile, Hugh Rollins, is later caught, but it becomes apparent that Kyle, whose body is eventually found in the woods, is not one of his victims. As a result, Prentiss confronts the Murphys and brings them into the local police station, where Lancaster has just falsely confessed to killing Kyle.
As his parents are questioned, Danny is left in the break room with Prentiss, who takes note of the fit of rage the boy goes into after being unable to open a bag of chips and the bored demeanor he has during a rerun of his parents' heartfelt plea for Kyle's safe return. Talking to the boy, Prentiss realizes Danny is Kyle's actual killer and that his parents and Detective Lancaster are trying to cover it up so Danny won't be taken away. After Kyle's autopsy report is brought to her by JJ, Prentiss leaves Danny with her and confronts the Murphys and Detective Lancaster. She asks if they know everything that Danny did to his brother. She then reveals that Danny stuffed model plane parts down his brother's throat and that Danny also killed their puppy earlier. Prentiss then tells them that Danny is a textbook sociopath in need of help, causing Dan and Sarah to break down. Afterward, it was presumed Danny was soon institutionalized in regards and for the murders of his puppy and Kyle.
Danny was described as a sociopath by Prentiss, which she stated made him incapable of feeling anything, such as empathy or guilt, most notably remorse (however, he is capable of feigning emotions, such as when he stated he was sorry after killing Kyle). It is hinted he did this after killing his puppy too. This was shown when Prentiss asked him how he felt after killing his brother and Danny's answer was a deadpanned "like I would get in trouble". He is also quick to anger and easily frustrated, as shown when he was unable to open a bag of potato chips and then began hitting the bag out of rage. Prentiss also mentions and talks about the puppy which the parents realize is true and it starts to make sense to them.
Since Danny is a young sociopath, the term "M.O." is somewhat misused as he regularly, uncontrollably and randomly flies into massive bursts of rage. He killed his puppy using unspecified means, however, he likely feigned emotions to his parents so they would refrain from contacting anyone. When killing his brother, he killed him in a fit of rage in an unspecified manner, though parts of one of Danny's model planes, which Kyle broke, were forced down his throat. This is almost certainly the cause of death and suffocation or strangulation is most likely, given this fact. The two blows to Kyle's head, with the first being more hesitant, were dealt by Detective Bill Lancaster in his attempt to make Kyle's death look like the work of Hugh Rollins.
Danny may have possibly been based on Burke Ramsey, the possible killer of JonBenét Ramsey - Both cases involved a younger sibling killed by their older brother (possibly in JonBenét's case) in a fit of rage, and both murders (possibly in JonBenét's case) involving toy sets of large vehicles (trains in JonBenét's case, planes in Murphy's). However, it should be noted that while Burke Ramsey testified before a grand jury, he was never considered or treated as a suspect in his sister's murder.
- April 20-21, 2009: Kyle Murphy
- At the age of nine, Danny Murphy is the youngest killer in the show's history thus far.