Editor's note: This story discusses suicide. If you or someone you know is having thoughts of suicide, please contact the National Suicide Prevention Lifeline at 1-800-273-TALK (8255).
The 16-year-old pageant star died by "asphyxia due to ligature hanging and the manner is suicide," according to authorities.
"The Whatcom County Medical Examiner's Office has completed an examination on a 16-year-old female," the release states.
"Her identity will not be released here out of respect for the family. The female was found deceased on May 2, 2022, in Blaine, Washington. The cause of death is asphyxia due to ligature hanging and the manner is suicide.
"The autopsy and toxicology reports are not public information."
Fox News Digital has contacted the Washington State Patrol trooper handling the investigation.
Posey’s mother, Marcy Posey Gatterman, posted about her daughter's death on Facebook last week.
"I don’t have words or any thoughts," she wrote. "A beautiful baby girl is gone. Please give us privacy as we mourn the loss of Kailia. My baby forever."
Posey’s last competition before her death was in the Miss Washington Teen USA pageant in February, where she placed second runner-up and also earned the Miss Photogenic award based on public votes.
Maureen Francisco, the executive producer of NW Productions, LLC, worked with Posey at the Miss Washington competition earlier this year and was shocked by Kailia's death.
"When I first saw the post that her mom posted about Kailia, I was in shock, I didn’t believe it," Francisco said. "At first, I thought maybe her mother’s Facebook got hacked, so I had to wait. I realized it wasn’t going away, that this is actually real. That’s when it really hit me — like wow.
"She was such a nice gal. She was so nice to our team, fellow contestants. I just remember her during pageant weekend, and she was constantly smiling, laughing, and she is a typical teen. The energy around her … she is definitely going to be greatly missed."
Posey first found fame on the hit TLC show "Toddlers & Tiaras" when she was just five years old, and lives on in meme history as the "Grinning Girl" from a 2011 episode. The show also launched the career of Alana Thompson, aka Honey Boo Boo, and her family, who produced multiple spin-offs.
Posey continued competing on the pageant circuit long after the reality show had ended in 2013 and a short-lived revival of the program in 2016.
"This young woman has so much potential, so much potential, and it’s just hard to wrap your mind around someone with so much potential and how they are gone too soon," Francisco said. "Again, the family has been nothing but nice to Pageants Northwest. Kailia has been wonderful to work with, with our team, with our fellow contestants. Just absolutely nice.
"That’s what I am going to remember most is her kindness."
Francisco recalled a moment during the Miss Washington Teen USA pageant when Posey’s personality was on full display.
"I remember when I was emceeing the pageant, and she answered her top five questions. She had the whole audience laughing, and I was trying really hard not to smile as well because I didn’t want to show favoritism," she said. "That’s the kind of energy she gives. Again, going to be greatly missed, and I am still racking my mind that this is real.
"She is going to be missed. I mean this is a huge loss to the pageant community, to the world and just so much potential."
Fox News' Larry Fink and Janelle Ash contributed to this report.