Chris Cornell, a key figure in the grunge rock movement as the banshee-voiced singer in the seminal Seattle band Soundgarden, committed suicide in a hotel room after playing a Wednesday night concert with the Grammy-winning group, authorities said.

Cornell, 52, was found dead early Thursday in his room at the MGM Grand Detroit hotel and casino, police said. The Wayne County Medical Examiner’s Office ruled his death as suicide by hanging. A full autopsy report has not been completed, the medical examiner said in a statement.

Police said a family friend called 911 around midnight after finding Cornell unresponsive on the bathroom floor in his hotel room. He was pronounced dead a short time later.

“His wife Vicky and family were shocked to learn of his sudden and unexpected passing,” Brian Bumbery, a publicist for Cornell, said in a statement. The singer’s family, Bumbery said, “would like to thank his fans for their continuous love and loyalty and ask that their privacy be respected at this time.”

Cornell, who had a complicated relationship with his rock-and-roll fame, was on tour with Soundgarden, which was in the midst of making its first new album in five years. The band performed, as scheduled, at Detroit’s Fox Theatre on Wednesday and was headed next to Ohio, to headline the Rock on the Range festival in Columbus.

“Finally back to Rock City!!!!” Cornell tweeted from Detroit just hours before his death.

Alongside the likes of Nirvana, Mudhoney and Alice in Chains, Soundgarden was one of the most important and successful bands in the loosely defined grunge movement that roared out of the Pacific Northwest in the 1990s and ushered in a new era of rock.

Co-founded in Seattle in 1984 by Cornell with bassist Hiro Yamamoto and guitar wizard Kim Thayil, Soundgarden made loud, sludgy music that evoked the proto-heavy metal of the 1970s, with a jagged punk edge.

The band became one of grunge’s first to sign with a major label after making several independent recordings – first with Sub Pop, a small Seattle record label that helped launch the culture-changing grunge movement.

Cornell played rhythm guitar but was best known for his throaty, multi-octave voice, which he once called “unapologetically male.”

“He comes from the Robert Plant school of vocalists, more banshee wailing than guttural bellowing, and possesses a set of pipes that ensures his voice is the focal point of whatever he’s singing, no matter what other musical mayhem may unfold,” The Washington Post wrote of Cornell.

Soundgarden’s music – which could be brooding, beautiful and bombastic, sometimes all at once – resonated with listeners at a time when hair metal and New Wave competed for chart space. The band’s songs were laden with emotion, and more often than not, that emotion was anger.

“For me to make a connection with music it has to either have a visceral nature, whether it’s anger or aggression or that kind of passion which shows up in rock music, or there has to be some sort of melancholy and introspection, something about it that makes you feel your own pain,” Cornell told Rolling Stone.

Of his band’s sound, perhaps the heaviest in grunge, Cornell told the Guardian: “If you’re an American kid, you can’t help but be influenced by Led Zeppelin, Black Sabbath and the Rolling Stones because they’re always on the radio. But from 17 to 19, all I listened to was Elvis Costello and the Beat. When Soundgarden formed we were post-punk – pretty quirky. Then somehow we found this neo-Sabbath psychedelic rock that fitted well with who we were.”

As grunge blasted into the mainstream, Soundgarden’s reach grew.

The group’s major-label debut, 1991’s “Badmotorfinger,” went multiplatinum and produced Soundgarden’s first MTV and radio hit, “Rusty Cage,” which Spin later called “emblematic of grunge’s rock-mutt DNA … punk spirit tempered with rock-star bravado, metal riffs forged with pop smarts.” The magazine added that the group’s sound “was a raw, threatening ferocity that made radio metal seem immediately gauche, but played with arena-ready chops that could beat them at their own game – and you can hear both in frontman Chris Cornell’s fire engine wail.”

The band’s next album, 1994’s “Superunknown,” topped the Billboard 200 charts and dominated rock radio, with hit single (“Spoonman”) after hit single (“Black Hole Sun”) after hit single (“Fell on Black Days”). A follow-up album, “Down on the Upside,” reached No. 2 in 1996.

By then a multiple Grammy Award winner, Soundgarden went on hiatus in 1997, although most fans assumed the group had broken up. Its members did little to dispel that notion: In a 2009 interview with The Post, Cornell casually referenced “the split-up of Soundgarden.”

“So at some point, might we see a Soundgarden reunion?” The Post asked.

“You never know,” Cornell replied.

With Soundgarden’s members having gone in separate directions, Cornell founded the rock supergroup Audioslave with Tom Morello, Tim Commerford and Brad Wilk, three members of Rage Against the Machine. That band eventually broke up, but reunited in January to play a Southern California concert in protest of President Trump.

Cornell also recorded numerous solo albums.

But always, he said, people wanted to know about his old band.

“Every time I did an interview, I was asked, ‘Is Soundgarden ever going to get back together? Will the band ever do anything again?’ ” Cornell told Gibson.com in 2011.

Indeed, it would. Soundgarden returned at the end of 2012 with the well-received “King Animal.” Its fans were still around and hungry for new music, it seemed, as the album reached No. 5 on the big Billboard chart.

Cornell’s beginnings were a little more humble than his success might suggest.

“I was going to be a musician, no matter what it took,” he told ESPN. “I supported myself with blue-collar jobs so I could write music and be in a band and play shows.”

And musician he was, but he found himself playing in a cover band called the Shemps when he was 18. He wanted to write and perform his own music, as he recalled to Richmond’s Style Weekly.

“I was driving home from a restaurant gig thinking: ‘It doesn’t matter to me if it’s hugely successful, it matters that we get to create our own songs and art. I don’t care if I have to break concrete if that supports the art,’ ” he said. “I didn’t want to play Police covers in the back of a Chinese restaurant, that’s not me. … Something felt really settled in me when I thought that.”

With Soundgarden, Cornell found creative satisfaction – and, eventually, fame, though as he told Style Weekly: “We weren’t a band that had overnight success. It came slowly and with a lot of effort.”

“The thing that was amazing about Soundgarden is that they were just so natural; it was just like this effortlessness to the whole thing,” Sub Pop co-founder Jonathan Poneman once told an interviewer. “There was this unholy mixture of Black Sabbath and the Butthole Surfers, which at the time was totally revolutionary. … There was some Zeppelin thrown in there, and there was more than a little Black Flag thrown in there, particularly in Kim’s guitar playing.”

For years before its breakthrough, Soundgarden was at the center of a thriving underground music scene in the Pacific Northwest.

The Seattle-based scene became “a bona fide phenomenon, a success story in a nation starving to hear one,” Rolling Stone wrote in 1992, noting the “spectacular success” of Soundgarden, along with Alice in Chains, Pearl Jam and Nirvana.

“For major labels, the gold rush is on,” Rolling Stone said in a profile of the new “rock mecca.” Bands from the region “are getting signed at the rate of one a week.”

“The bands that created the scene are the bands that are out there getting the benefits of what they created,” Cornell said at the time. “And what’s come in after that was never a scene to begin with. This scene was basically bound to end one way or another, and it’s a happy ending in that the bands that started it are all having some good success.”

But Thayil would say years later that the band found its commercial success strange.

“We really couldn’t anticipate the commodification of the band,” the guitarist told Rolling Stone last year, adding that it “is emotionally and creatively difficult to balance your understanding of what you’re doing as a songwriter or musician and then having to understand it as something that exists out there in posters and videos and record sales. It’s kind of a weird thing.”

For Cornell – the most visible member of the group, a mesmerizing frontman with a flowing mane and piercing blue eyes – fame came at a steep price. He spent time in rehab for “various things,” but “mainly for drinking,” he told Spin. According to him, it was a way to escape his fame, which he found isolating.

“I’m Irish: If I could get the cap off something, I would drink it. And drinking was really an extension of becoming isolated from all my other relationships,” he told the magazine, remembering the first time he was recognized “at four in the morning, in the middle of Mississippi” after the music video for his song “Outshined” played on MTV for the first time.

After that, he tried avoiding the public. Drinking made that easy.

“I never liked being recognized to begin with, and I was never much of a social person, so this gave me a chance to play the ‘I don’t want to go out’ card,” he said. “I would just stay in and drink.”

“I could drink a lot, and I tended to have violent outbursts,” he added.

In 2002, he “had to come to the conclusion, the sort of humbling conclusion that, guess what, I’m no different than anybody else, I’ve got to sort of ask for help – not something I ever did, ever,” as he told Blabbermouth, so he checked himself into rehab.

“I actually like rehab a lot,” he told Spin. “It’s like school; it’s interesting. I’m learning that I can be teachable at age 38.”

Having returned to the road – and the recording studio – with Soundgarden, Cornell seemed to be enjoying the reunion.

A tweet posted by the band’s official account Tuesday quoted Cornell on “camaraderie.”

“When I do solo tours, I’m really kind of alone all the time, so that’s the best thing about it,” Cornell told Billboard about being back on the road with his old band.

Writing in the Oakland Press, veteran rock critic Gary Graff noted that Cornell “was in fine form” during the band’s concert in Detroit on Wednesday, “showing off his wide vocal range and room-shaking screams throughout the concert. He was in high spirits as well, frequently cheering the audience’s enthusiastic response.”

But the night ended on an eerie note.

According to Graff, during the finale, Cornell sang part of a Led Zeppelin cover.

The song? “In My Time of Dying.”

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