Aaron Carter of the Fantasticks Off-Broadway Show performs at the New York Stock Exchange on the day of the 88th Annual NYSE Christmas Tree Lighting on Wall Street In New York City on December 6, 2011. UPI/John Angelillo | License Photo
Nov. 6 (UPI) -- Nick Carter broke his silence Sunday regarding the death of his younger brother and fellow singer, Aaron.
Aaron, who battled substance abuse issues and mental illness for years, was found dead in the bathtub of his California home Saturday. He was 34.
The cause of his death has not yet been publicly disclosed.
"My heart is broken. Even though my brother and I have had a complicated relationship, my love for him has never ever faded," Nick, a member of the Backstreet Boys pop group, wrote on Instagram, alongside a photo gallery of him and Aaron as young boys.
"I have always held on to the hope that he would somehow, someday want to walk a healthy path and eventually find the help that he so desperately needed. Sometimes we want to blame someone or something for a loss, but the truth is that addiction and mental illness is the real villain here. I will miss my brother more than anyone will ever know. I love you Chizz. Now you can finally have the peace you could never find here on earth....I love you baby brother."
Aaron's twin sister Angel also shared some special photos on Instagram.
"To my twin... I loved you beyond measure. You will be missed dearly. My funny, sweet Aaron, I have so many memories of you and I, and I promise to cherish them," she wrote. "I know you're at peace now. I will carry you with me until the day I die and get to see you again."
His on-off partner, Melanie Martin, told TMZ: "My fiancé Aaron Carter has passed away. I love Aaron with all my heart and it's going to be a journey to raise a son without a father.
"Please respect the privacy of my family as we come to terms with the loss of someone we love greatly," she added. "We are still in the process of accepting this unfortunate reality. Your thoughts and prayers are greatly appreciated."