2:37 PM PT -- 9/1 -- Luke Bell's family tells TMZ ... "We have lost our beloved son, brother and friend and we are heartbroken. Luke had a gentle heart, a wanderer’s spirit and a musical gift that he was fortunate to share with us and the world. We are so grateful to his friends and fans for embracing Luke and his music. We would like to thank all of Luke’s fans, friends and family who have been sharing stories and photos of happy times with him."
"Unfortunately Luke suffered from the disease of mental illness, which progressed after his father's death in 2015. Luke was supported through his disease by a community of loving family and friends. Despite this, he was unable to receive the help he needed to ease his pain. Our hearts go out to the millions of people affected by mental illness who, like us, understand the devastating disappointment of a system that consistently fails to provide caring solutions to those who suffer."
"As we navigate our heartbreak we respectfully ask for privacy to allow us room to grieve and honor his memory. Our only comfort comes in the fact that our Luke is finally free and at peace."
Country music singer Luke Bell battled severe bipolar disorder for years before recently going missing and being found dead ... and his manager says he'd disappeared a few times before.
Luke's business manager, Brian Buchanan, tells TMZ ... the singer tried to cope with bipolar disorder, but could never find a solution that worked for him. When Luke disappeared in the past, Brian says they were always able to track him down.
We're told the singer-songwriter was prescribed medication, but his manager wasn't sure if Luke was taking his meds earlier this month when he went missing in Arizona.
Cops say Luke's body was discovered Friday in Tucson, and Brian tells us he'd vanished one night while getting food in the area with his musician friend Matt Kinman.
We're told Luke and Matt were in Tucson to visit Matt's family and play some gigs. Matt had searched for Luke for at least 10 days before the body was found.
Police say an investigation is ongoing ... and we're told an autopsy is underway to determine the cause of death.
Luke's manager tells us ... "Luke fought this as hard as he could, but the disease got the better of him. When he was beating the disease, he was the sweetest and most generous guy. He's found peace now and there's some comfort."
Luke was 32.
If you or someone you know is thinking of suicide, please call the National Suicide Prevention Lifeline at 988.