“I need everyone to stop and pray right now for Heaven!” she wrote in all capital letters. “It’s an emergency!”
Heaven's cause of death was not stated. Her mother previously said that the teen suffered from bipolar disorder and was in a manic phase of the illness when she ran away, according to ABC News.
Heaven was reported missing Nov. 26 after her mother went into her room, believing the teen was sleeping in, and instead found her gone. Orange County Sheriff's Office investigators said at the time that the teen left a note indicating she was heading to California.
At the time of Heaven's disappearance, detectives believed that she might have fled the state with a much older man she met online. Cox posted in a now-deleted Facebook post, which was preserved by fact-checking website Snopes, that a friend told her Heaven had met the man on Snapchat.
"The man she has been talking to is a predator, who has apparently been manipulating her for some time, and in her current state of mind, she believes that he is her friend," Cox wrote. "She left a goodbye note to me and her dad and said that she wouldn't have a phone, so I'm sure he has taken it from her, as it isn't here, and I have torn her room apart."
Sheriff's Office officials announced on Nov. 30 that Heaven had been found safe in Louisiana, where she was at the home of a relative of an acquaintance. Preliminary reports indicated that she had left home of her own free will.
It was unclear at the time if she had left home to meet up with the older man from Snapchat. Investigators said at the time that the case remained under investigation.