She's dead, too.
Or rather, her character on the O.C., is. Marissa Cooper- killed when her car was run off the road after high-school graduation was over.
Well, that'll really mess up the O.C. reunion show whenever it happens, unless they decide to have one of these characters dream up this entire last season or something like that- and invite Mischa back. Heck, that's what they did on Dallas.
I dunno what's gotten into these writers in Hollywood. They're in a bloodthirsty mood, killing these women off all the time.