Cory Wells, a member of Three Dog Night, has died. The singer was 74 years old.

The group, which had a string of hits during the 1970s, announced Wells’ death on their website. They said that Wells died unexpectedly in Dunkirk, New York. A cause of death was not announced, but he stopped performing with the group last month after he had severe back pain.

“It is with deep sadness and disbelief that I must report the passing of Cory Wells, my beloved band mate for over 45 years,” Danny Hutton, another member of the group, said in a statement. Cory was an incredible singer – a great performer, he could sing anything. Cory was like a brother in so many ways. We had been together since 1965 and I am in shock at this sudden loss.”

Wells was a member of Whisky A Go-Go’s house band when he met Hutton and a Hanna Barbera Records producer. They were invited to tour with Sonny and Cher. After that, Hutton asked Wells if he wanted to join a group of three lead singers, leading to the creation of Three Dog Night.

Three Dog Night scored 21 straight Top 40 hits, mostly with covers. Their best known singles were covers of Harry Nilsson’s “One,” Hoyt Axton’s “Joy To The World,” Randy Newman’s “Mama Told Me Not To Come,” Elton John’s “Your Song” and Paul Williams’ “Out In The Country.” The group continued touring until this year. It’s not clear if they plan on going forward without Wells.

Wells was born in Buffalo, New York and is survived by Mary, his wife of 50 years; and his two daughters.