"While in her residency in New Orleans on Monday night, Ms. Allemand was found by her boyfriend, NBA basketball player Ryan Anderson, following an apparent suicide attempt," her family said in a statement.
Though the family has not confirmed the specific details of her death, TMZ reported Wednesday that Allemand hanged herself.
After Anderson, a forward for New Orleans Pelicans, called 911, she was taken to the hospital for what her family called a "serious emergency medical event."
"Due to a critical loss of brain and organ function, life support was withdrawn," the statement continued. "Ms. Allemand passed away peacefully with her mother, boyfriend, and other lifelong friends by her side. As a practicing Christian, Gia did receive the sacrament of last rites."
Allemand competed for roses on Jake Pavelka's 2010 season of the ABC dating series.
"I had to pull over, I can't stop crying. We have lost an angel," Pavelka tweeted. "I am in complete shock and devastated to hear the news about Gia. She was one of the sweetest people I have ever known."
Vienna Girardi, the winner of Allemand's season, gave this statement to TMZ:
Gia was a beautiful girl and an unbelievable friend. I’m shocked and can’t believe what happened to her. She seemed so happy, but you never know the demons people are fighting inside. I will never forget her and will miss my friend forever.
"It's with heavy hearts that we say goodbye to our good friend Gia Allemand," "Bachelor" and "Bachelorette" host Chris Harrison tweeted. "She will be loved and missed by all who knew her."
"Our hearts are so heavy in hearing the news on Gia. With everything that comes along with the Bachelor, the biggest gain that each of us walks away with is a new "family," Jason and Molly Mesnick told E!, "And our family has lost a beautiful soul far too soon. She will always be in our hearts, and our thoughts & prayers go out to Gia's family, friends, and loved ones."
Sean Lowe, the show's most recent "Bachelor," penned this tweet:
My prayers go out to @GiaAllemand 's family during this time. Life on earth is but a vapor and she's with our Lord now.— Sean Lowe (@SeanLowe09) August 14, 2013