In the letter, the 40-year-old television personality opened up about experiencing an "emotional breakdown" in the aftermath of her assault arrest against boyfriend Lewis Burton.
Flack stepped down as host of the popular ITV2 show following the December 2019 arrest.
"Within 24 hours my whole world and future was swept from under my feet and all the walls that I had taken so long to build around me collapsed," Flack wrote. "I am suddenly on a different kind of stage and everyone is watching it happen."
Flack intended to release the letter on social media but was ultimately advised against it by her team, her mother, Chris Flack, shared. The family deemed it appropriate to release it this week.
"So many untruths were out there but this is how she felt and my family and I would like people to read her own words," her mom Chris told EDP.
The somber apology continued with Flack claiming she had "taken responsibility" for her arrest, which she said was an "accident."
"I've been having some sort of emotional breakdown for a very long time. But I am NOT a domestic abuser. We had an argument and an accident happened. An accident. The blood that someone SOLD to a newspaper was MY blood and that was something very sad and very personal," the U.K. host continued.
She then shared she was "so sorry" to her family and friends.
"I'm not thinking about 'how I'm going to get my career back.' I'm thinking about how I'm going to get mine and my family's life back," she added.
Flack was found unresponsive in her London home Saturday. Days later, a London coroner's office ruled her death a suicide by hanging.
About two months prior, police responded to Flack's home based on reports that a man had been assaulted. The man allegedly injured was Flack's boyfriend.
Flack pleaded not guilty at the time of her arrest and was due in court in March.
ITV2, which airs "Love Island," reacted to Flack's sudden passing in a statement to Fox News on Saturday.
"Everybody at Love Island and ITV is shocked and saddened by this desperately sad news. Caroline was a much-loved member of the Love Island team and our sincere thoughts and condolences are with her family and friends," the statement read.
If you or someone you know is having thoughts of suicide, please contact the National Suicide Prevention Lifeline at 1-800-273-TALK (8255).