[Warning: Potentially Triggering Content] A man has pled guilty to helping murder his nephew in 2016, and then his niece in 2018, marking the latest major event in a shocking intra-family murder case that has absolutely rocked the state of Georgia for more than half a decade. Late last month, Mark Wright (pictured above, right) entered a guilty plea for his role in the 2016 death of Elwyn Crocker Jr., who was 14 when he died back in 2016, as well as the death of Mary Crocker, who was 13 when she passed away in 2018. According to multiple media reports from the small Georgia town of Guyton, Wright admitted to helping the kids' father Elwyn Crocker Sr. - a former Walmart Santa Claus (pictured above, left) - carry out the murders and then bury the children's' dead bodies on the family's rural property. Related: Idaho Murder Victim's Mother Makes Surprise Statement: She's Forgiven Bryan Kohberger! But beyond Wright's involvement alone, this entire story is absolutely jaw-dropping from start to finish. Seriously, it's beyond tragic and disturbing. Read on for the heartbreaking saga... Contents [hide] 1 An Indictment Years In The Making 2 A Grisly Double Murder 3 A History Of Abuse 4 Awful Text Messages 5 'Stalled For So Long' 6 Sentencing On Deck An Indictment Years In The Making Wright was first arrested for the murders way back at the very end of 2018 alongside the kids' parents Candice Crocker (who is also Wright's sister) and her husband Elwyn Sr. The elder Elwyn had been employed at the time by the aforementioned Walmart in the area, working as a Santa Claus in the store and having untold numbers of kids sit on his lap. Creepy... And they weren't the only arrests! Also nabbed by cops were Candice's mother Kim Wright and her boyfriend Roy Prater. Candice and Roy have already entered plea agreements in this case, BTW - so Wright's plea late last month marks the third such move. Related: Parents Of Supposedly Kidnapped Baby Arrested On Suspicion Of Murder! To that end, Effingham County District Attorney Robert Busbee said this to WTOC News after Wright admitted to his role in the murders and burials: "This case has weighed heavily on Effingham County for many years. While there is still a long road ahead, today's plea is an important step toward accountability and justice for Elwyn Crocker Jr. and Mary Crocker. I am relieved that this matter is finally moving forward after being stalled for so long. Our office remains committed to seeing this case through to its conclusion." Remember that "stalled for so long" remark, because it'll come back later. But anyways... A Grisly Double Murder So, s**t hit the fan on December 20, 2018 after a relative of the Crocker fam called the cops in Guyton and said she hadn't seen little Mary Crocker since October. Cops showed up at the Crocker family compound and began questioning Elwyn Sr. about that. Based on what police officials later said were his super-sus responses, they went out into the backyard and started looking around. Very quickly, they found a recently-dug hole. In it, they uncovered the bodies of both Mary and her older brother Elwyn Jr. Both kids had been homeschooled at the time, so neither one had been reported missing by anybody. Had it not been for that suspicious relative, who knows when this all would have come to light! And that's especially disconcerting because, as we noted up top, Elwyn Jr. was actually murdered two years before Mary, in 2016. Nobody had thought to check on him, so conceivably his killers could have gotten away with it forever. Elwyn Jr.'s body was way too decomposed for forensic pathologists to tell how he had been killed. But in May of this year, Dr. Edmond Donaghue, an ex-medical examiner for the Georgia Bureau of Investigators, testified in court that Mary's body mass index was just 8.6 when she died. For reference, the BMI of an average young adult is between 20 and 25, with a slightly lower number often typical for teenagers like Mary, per various government public health departments. So, to be at just 8.6 even as a 13-year-old is absolutely crazy. Dr. Donaghue testified to that effect, saying he'd "never seen such a low number" in a human before. In fact, Mary was so small at the time of her death that "her body length was under 2nd percentile" and "her actual weight was below 1st percentile" for her age, according to the doctor's testimony. WTF... A History Of Abuse According to multiple local news outlets, the Georgia Division of Family and Child Services first became involved with the Crocker fam back in 2012 after they received reports that Elwyn Jr. was being abused. The DFCS rooted around for a while on that allegation and eventually ordered Elwyn Sr. and Candice to undergo therapy and parenting classes. However, the agency ultimately closed its case in 2013. But the abuse apparently didn't stop. Not by a long shot. Per court documents cited by WJCL News, for the final ten months of Mary's life throughout 2018, she was allegedly