how can i set this girl up.?

[Krz Krzz]

i have a classmate. she is the real thief, but everyone thinks i am. because of some happenings. but i swear i am not! so please help me. this girl is the real thief! i said that becuase, i saw her came in the room before me. but everyone thinks im the thief coz i am the last person to go inside that room. i need to prove everyone that she is the thief. my friend told me, that if i display my cellphone ( blackberry ) in my desk when people are gone, i think that no one will try to get it. EVEN my thief classmate. why? because they will think that someone is spying on them. so i need to set her up. but how. i thinking of putting my cp on her bag. but i think they will get suspicious and they will said, that girl just set her up so that she will not be blamed anymore. any good ideas? pleaaase?