From kissonline:

"Sad to report that Mark Norton aka Mark St. John, KISS' lead guitarist on Animalize, passed away this morning of a cerebral hemorrhage. Mark was 51 years old.

KISS remembers Mark for his contributions and sends their condolences and deepest sympathies to his family and friends."

Mark was in KISS when Gene and I started working together - in fact, the guitar amps you hear on "The Right To Rock" album were mark's Marshalls, which he loaned us. He would often hang at the studio with us, and offered a lot of support in addition to the use of his gear.

He was a great guy and a very underrated talent, and he'll be missed. Below is a photo of Mark and I at NAMM in 1985.

His work with the band White Tiger was absolutely amazing... Arguably one of the most talented(and underrated) guitarists to play in KISS...

So sorry to hear this my prayers go out to his family and friends.

Actually, if you take away that weird Rockman tone that he used on "Animalize", what he played was really cool. He was probably the best guitarist to ever play in KISS. Sorry to hear about his passing----over the years he definitely got dealt a bad hand health-wise.

Got this sad news just yesterday. I have a cassette of White Tiger and it sounds really nice, haven't check out his works with Kiss but I will try to get that record. R.I.P. Mark