The message was posted on Marlin "Lilly" Dean's Facebook wall about 5 p.m. EST Thursday. It said she missed everyone, especially her sisters, and asked for forgiveness regarding the manner in which she left the area.
On Nov. 2, the Columbia County Sheriff's Office said the teen had been found in Mexico, was safe and was expected to return to her Harlem home the following week.
Sheriff's Capt. Steve Morris had refused to provide details of where and when Marlin had been found or whether she was with anyone.
The 17-year-old was last seen locally Oct. 19 near Augusta Mall.
Marlin is the oldest of five siblings from Guatemala who were adopted by Scott and Renee Dean in 2008.
On Oct. 27, four children were removed from the Deans' Harlem home by a Division of Family and Children Services caseworker and later released to a family member.
Officials have refused to discuss why the children were removed, but Dean issued a statement that DFCS was called in to assist in the search for Marlin.
Dean also said that "allegations, insinuations and lies were leaked to the media" that caused "irreparable harm" to his family.
Marlin's latest Facebook post apparently addressed those allegations.
"Please don't believe what they are saying about my dad, cuz ITS NOT TRUE, he is the best daddy i ever had," the post read.
A follow-up message read:
"Daddy im sorry, like i told you u are the best, let me tell yall he didnt do all those things that the news are saying ... please dont believe bad things hapened to me, and i choose to write this on facebook cuz that way all yall can know."
Morris wrote in an e-mail that he was aware of the post but did not want to comment further.
For nearly a month, there has been no activity on Marlin's Facebook page.
Before Tuesday, the last message posted on her wall was typed in Spanish to her sister, Sindy, on Oct. 22 -- three days after she was reported missing.
The message translated as: "Hello Sindy, I'm fine ... take much care and call me when you can or (text me)."
On Nov. 2, Columbia County voters re-elected Dean to the District 4 commission seat. He was unopposed in the general election.