Chris Cornell Was in 'Great Spirits' Shortly Before His Death, Friends Say: 'It's a Complete Shock'

Fans and loved ones of rocker Chris Cornell are reeling after his shocking and unexpected death at age 52.

Cornell, who first gained fame as the lead singer of Soundgarden and later the band Audioslave, was found in his hotel room at the MGM Grand Detroit following the band’s performance at the Fox Theatre, his rep and Detroit police confirm to PEOPLE.

The Wayne County, Michigan medical examiner completed an autopsy Thursday afternoon and confirmed that Cornell died of suicide by hanging.

“Chris seemed in really great spirits and everyone is in complete shock,” a friend of the rocker and wife Vicky Karayiannis, who saw them recently, told PEOPLE.

Cornell had recently written and performed the end-title song for The Promise, a film that addressed the Armenian genocide. On April 18, he attended a screening at New York’s Paris Theater, accompanied by Karayiannis and their two children: daughter Toni, 12, and son Christopher, 11.

“He was an incredible family man,” an additional source tells PEOPLE. “He loved all of his children. In the last month, he had just completed a tour for The Promise — he brought his daughter and wife with him…He was an incredible human, an incredible father, and it’s a f— shock.”

“I can tell you that he was a beautiful, caring, generous and sweet friend, and he always acted like a big brother to me,” The Promise producer Eric Esrailian told PEOPLE exclusively. “I know that his whole world revolved around his wife and children, and he was just such a dedicated father, but also very much the type of person who took such joy and pride in his children.”

A concertgoer tells PEOPLE that Cornell was enthusiastic and energetic during his sold-out final performance Wednesday night.

“If something was wrong, he didn’t show it. He seemed to be genuinely excited to be performing in Detroit,” the concertgoer said.

Cornell ended the set with a cover of Led Zeppelin’s “In My Time of Dying,” CNN reported.

“In my time of dying, I want nobody to mourn/All I want for you to do is take my body home,” Cornell sung.

If you or someone you know is considering suicide, please contact the National Suicide Prevention Lifeline at 1-800-273-TALK (8255).

• Reporting by ANDREA BILLUPS, JEFF NELSON and NICOLE SANDS