Megadeth have “parted ways” with co-founder David Ellefson following allegations of sexual misconduct against him.
The bassist has been accused of trying to groom an underage girl online, and denies the allegations.
On Monday, Megadeth released a statement to say Ellefson was no longer part of the band.
It said: “We are informing our fans that David Ellefson is no longer playing with Megadeth and that we are officially parting ways with him.
“We do not take this decision lightly.
“While we do not know every detail of what occurred, with an already strained relationship, what has already been revealed now is enough to make working together impossible moving forward.
“We look forward to seeing our fans on the road this summer and we cannot wait to share our brand new music with the world. It is almost complete.”
Mustaine also signed the release.
Ellefson has used his Instagram account in the past to deny the allegations, but it has since been made private.
He said the messages were “private, adult interactions that were taken out of context and manipulated to inflict maximum damage to my reputation, my career and family”.
The 56-year-old left the band in 2002, but rejoined eight years later.
Megadeth is considered one of the big four US thrash metal bands, along with Slayer, Metallica and Anthrax.