The Doobie Brothers' original drummer and co-founder John Hartman died on September 23rd of undisclosed causes at age 72, according to Variety. Hartman, who, initially was the band's sole drummer, was an integral part of the Doobies during their meteoric original run. Starting in 1973, he drummed alongside second drummer Michael Hossack who was then replaced by Keith Knudsen.
Knudsen died on February 8th, 2005 at age 56 from complications related to pneumonia.
Hartman split from the band in 1979 only to join forces with the Doobies again on their initial reunion albums — 1989's Cycles and 1991's Brotherhood, after which he retired from the music business. He was inducted alongside the Doobie Brothers into the Rock and Roll Hall of Fame in 2020.