Malcolm Young, guitarist and co-founder of Australian legendary rock band AC/DC, died Saturday at the age of 64. Young had been suffering with dementia for the past three years, an illness that forced his retirement from the Rock and Roll Hall of Fame-inducted band he founded with his brother Angus Young in 1973.

“Today it is with deep heartfelt sadness that AC/DC has to announce the passing of Malcolm Young,” AC/DC wrote in a statement.

The Young brothers lost their older brother George Young, the Easybeats guitarist and AC/DC's longtime producer, in October at the age of 70, reports Rolling Stone. 

In an additional statement from Malcolm Young's family, the band said that Malcolm Young died peacefully Saturday with his family by his side.

As rhythm guitarist for the legendary rock band, Malcolm Young served as an indispensable foil to Angus Young's arena-stuffing riffs. After forming AC/DC in 1973, the Young brothers would be credited as co-writers on every song the band recorded from their 1975 debut “High Voltage” through 2014's “Rock or Bust”. That final album marked AC/DC's first without Malcolm, who announced in September 2014 that he would permanently leave the band due to dementia.

Malcolm Young last performed live with AC/DC when their tour for 2008's “Black Ice” concluded in June 2010 with a concert in Bilbao, Spain.

Like his older brother George and younger brother Angus, Malcolm was born in Glasgow, Scotland before the whole Young family migrated to Sydney, Australia in the early '60s.

In 1973, Malcolm recruited Angus to form a new band, which the brothers named after the “AC/DC” electrical current marker they spotted on their sister's sewing machine. After a few lineup changes, the Young brothers were introduced to singer Bon Scott by their brother George, who would serve as AC/DC's producer on their early albums.

Throughout AC/DC's tenure, Malcolm and Angus Young served as the band's main creative force, crafting the unmistakable riffs that would make AC/DC one of the biggest bands in music. Together, the brothers would create the music for hits like “Back in Black”, “Hells Bells”, “Highway to Hell”, “Thunderstruck”, “For Those About to Rock (We Salute You)”, “You Shook Me All Night Long” and dozens more rock staples.

The Young brothers and AC/DC were inducted into the Rock and Roll Hall of Fame in 2003. With over 110 million albums sold, AC/DC is also the best-selling Australian act of all time.

Source: Rolling Stone