John Muir, author of "Wes Craven: The Art of Horror", was critical of the new characters introduced in "Scream 2" – Derek, Joel, Cici, Hallie, Lois, Murphy and Mickey – stating that they never attained the same depth of character as "Scream" characters such as Tatum Riley, Billy Loomis and Stu Macher, or even minor characters like Principal Himbry. Muir cited the sequel's focus on increased body counts and violence as the cause of this discrepancy in the quality of the two films' characters. He added that, as a result, "Scream 2" lacked the same mystery or intrigue as the original, as the killer could be any character, purely because the audience is never provided with enough information to form an opinion of them. Roger Ebert agreed with this criticism, saying "there is no way to guess who's doing the killing, and everyone who seems suspicious is (almost) sure to be innocent."