According to TMZ, Keith Emerson died from an apparent self-inflicted gunshot.

Law enforcement sources tell the site the EMERSON, LAKE & PALMER keyboardist had a single wound to the head when his girlfriend found him in their home in Santa Monica, California.

Sgt. Erika Aklufi of the Santa Monica Police Department confirmed in a statement that "Keith Emerson's death is currently being investigated as a suicide."

Emerson had reportedly been suffering from a degenerative nerve disease in his right hand that meant he could only play the keyboards with eight fingers. As a result, he was struggling with depression.

Back in 2010, Emerson revealed that he had undergone surgery for diverticulitis.

In addition to Emerson, EMERSON, LAKE & PALMER included vocalist/bassist Greg Lake and drummer Carl Palmer.

Palmer said in a statement that he was "deeply saddened to learn of the passing of my good friend and brother-in-music."

EMERSON, LAKE & PALMER reunited for one last tour together in 2010. Their final gig took place in July 2010 at London's High Voltage festival.