Though further details are still unknown. TMZ was first to report Ashley’s death.
William and Christy Mattingly tell PEOPLE that their sister lived in Travis County outside of Austin, Texas, and they received news of her death late Thursday.
The model was found unresponsive on Thursday after a friend called police asking for a wellness check because they had not heard from her, William and Christy say.
The investigation into Ashley’s death is still ongoing, and her siblings have not yet been able to read her note.
The Austin Police Department tells PEOPLE that the incident occurred in Bee Cave, Texas, which is about 15 miles northeast of Austin. The Bee Cave Police Department did not immediately respond to PEOPLE’s request for comment.
“We learned late Thursday night that it is believed that our dear sister with a larger-than-life personality took her own life,” William and Christy say in a statement provided to PEOPLE on Monday.
“Ashley moved closer to home a couple years ago and was living in Austin. It’s maybe no secret that Ashley struggled with alcohol and substance abuse, but she wanted to and was working toward getting better,” they say.
“We are now loving on her sweet golden retriever puppy that she recently adopted to overcome these demons,” their statement continues. “A friend, whom we are thankful for, called the police for a wellness check and she was found unresponsive her in home. As part of an ongoing investigation, the police have notes that we are told she left behind and we are anxious to read them. She will continue to live on through nieces whom she loved dearly and always thought of no matter how far away she was, a twin brother, two sisters and numerous other friends and family members. We will forever cherish her memories and know that her joy is eternally sealed. We look forward to seeing her again.”
“Our hope is that Ashley’s story can continue to shed a light on suicide awareness and prevention,” the statement concludes. “We love you Ashley.”
Fellow former playmate Carrie Stevens shared her grief upon hearing the news of Ashley’s death, and shared a photo of the two women with Hugh Hefner, who died in 2017.
“I am devastated,” Stevens, 50, wrote on Twitter. “My friend #ashleymattingly took her own life. If you are struggling please reach out for help. She was only 33 RIP #playmatesister.”
Ashley appeared as Playboy‘s Miss March in 2011.
In 2016, Ashley was arrested on suspicion of driving under the influence in Laguna Beach, California, TMZ reported at the time, though she denied the charge. In 2012, her boyfriend at the time was accused of slapping Ashley, but he denied any domestic abuse.