Rapper Lil Peep has died at 21. His representative confirmed the news on Thursday after the rapper, whose real name was Gustav Ahr, did not appear at a scheduled concert in Tucson on Wednesday.

Police in Tucson, Arizona, said Ahr, was found dead on his tour bus in the city Wednesday night, reports the AP. Sgt. Pete Dugan said evidence pointed to an overdose of the anti-anxiety medication Xanax, but no official cause of death has been announced.

In a statement, First Access Entertainment CEO Sarah Stennett said she is "shocked and heartbroken" over the death. She added, "I do not believe Peep wanted to die, this is so tragic. He had big goals and dreams for the future which he had shared with me, his team, his family and his friends." Stennett also said that Ahr's mother said "she is very, very proud of him and everything he was able to achieve in his short life."

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Ahr was known for his "emo rap," as GQ called it, and his tattoos and style. He sat front row at several fashion shows in Paris in June.

Ahr's manager, Chase Ortega, reportedly tweeted a cryptic message after the rapper's death, saying, "I've been expecting this call for a year. Mother f**k," Billboard reports.

Ahr, who was from Long Beach, New York, was dating model Arzaylea Rodriguez when he died. She posted an emotional tribute on Instagram. She wrote, "I can't believe i'm writing this. you're in my heart. i'm always yours. I don't have words to express what you've done for me in such little time. I love you so much. You live forever in me. I don't know how to do any of this without you now... I love you so much. I want to wake up from this nightmare."

Ahr's collaborator, Mikey Cortez, wrote on Instagram, "I'm completely heartbroken and lost right now. I can't even feel it's not real. I love you and I'll miss you always. One of the realest. Please someone tell me this isn't real."

I’m completely heart broken and lost right now. I can’t even feel it’s not real. I love you and I’ll miss you always. One of the realest. 😢. Please someone tell me this isn’t real. A post shared by Ralph Lauren Cholo 🐎 (@mikeycortez) on Nov 15, 2017 at 9:34pm PST

Many artists, including Charlie XCX, Sam Smith and Mark Ronson, took to Twitter to pen tributes to the rapper.

lil peep passing is such a tragedy. i remember hearing him for the first time and being so enthralled. love to all his family, friends and fans. we have lost something special. R.I.P. — CHARLI XCX (@charli_xcx) November 16, 2017

Seeing the news of Lil Peep is so desperately sad — Sam Smith (@samsmithworld) November 16, 2017

tragic about Lil Peep. 1st time i saw this vid, I got chills. + flashes of what the future of gtr music might b https://t.co/w0XyM3HjuW via — Mark Ronson (@MarkRonson) November 16, 2017

peep had so much more to do man he was constantly inspiring me. I dont feel good man — diplo (@diplo) November 16, 2017

Peep was the nicest person. hanging out with him, talking to him about music, the song ideas we were going to do together and touring was so amazing. Everyone will miss you man @Lilpeep — marshmello (@marshmellomusic) November 16, 2017

I remember Lil peep telling me he is against the sexual abuse of women and people in the music industry... I will continue to push his vision thank you - Lil B — Lil B THE BASEDGOD (@LILBTHEBASEDGOD) November 16, 2017