A third person has been arrested in connection with the death of a 4-year-old Aurora boy who police say was beaten to death.Chyann Moon, 23, was arrested Thursday on suspicion of felony child abuse resulting in death, knowingly and recklessly, according to a release from Aurora Police. According to an affidavit, Moon is the girlfriend of the man accused of murder in the child's death.The boy had been found unconscious and not breathing with "significant injuries" at Moon's apartment around 10 p.m. before being rushed to a local hospital, where he later died, police say.He died May 16, and Alexander Martinez-Armstrong, 24, was arrested that day on suspicion of first-degree murder. Police say Martinez-Armstrong, who was not the boy's father but served as a caretaker and "godfather," "acknowledged striking the boy repeatedly" before his death.Several days later, police arrested the boy's mother, 23-year-old Destini Rose Lipsky, on suspicion of child abuse resulting in death.Martinez-Armstrong and Moon told police the boy had been "relinquished into their care and custody for at least several days to 'correct' the child's 'behavioral issues,'" according to the affidavit for Martinez-Armstrong's arrest.According to the affidavit, Martinez-Armstrong told police he had permission to punish the boy "using the same methods she used," which he said he had witnessed, which included belt whippings, open-palm spankings, push-ups, planks and wall-sits.The mother told police she would use similar forms of "punishment," "but never in a manner to inflict injury or to leave a mark," the affidavit says. She said she didn't think Martinez-Armstrong would "hurt" her child, according to the document.The paramedics dispatched to Moon's apartment reported that the boy was in cardiac arrest, according to the affidavit. The boy also had bruising of various stages of healing covering his "entire body from head to toe," per the document.On the day of the child's death, Martinez-Armstrong told police he had hit the child with a belt at least 21 times, the affidavit says. Moon, who police said changed her story multiple times, said she had witnessed belt whippings several times before they found the child unresponsive and called 911, according to the filing. ...read more read less