In 2005 he was charged with criminally harassing his wife. He spent two years in jail awaiting trial before he was diagnosed with Capgras syndrome, a condition that made him believe his wife and daughter had been replaced by impostors. He was committed to a mental institution.

Marcello was a synthesis of every Italian idiom that I could nurture out of my heart and soul. I began to realize that all great comedic actors from Curly Howard on had one character, which was the epitome of who they were. And so on that basis, Marcello got me on SCTV, and on "Saturday Night Live". You need one character that you can really put all your chops into and jazz with and jam with.