Final answer:
The character who throws fake letters outside Brutus' window in Shakespeare's 'Julius Caesar' is Cinna the Poet, not a senator.
Step-by-step explanation:
The student's question pertains to a character in William Shakespeare's play Julius Caesar. Neither the play nor historical records attribute the action of throwing fake letters to any specific Roman Senator, instead, the character responsible for this deceit is a man named Cinna the Poet. In Act 1, Scene 3, it is Cinna who is tasked by Cassius to plant forged letters in Brutus' seat at the Senate and to throw others through Brutus' window, all with the intention of persuading Brutus to join the conspiracy against Julius Caesar. These letters are meant to appear as though they are from Roman citizens who are concerned about Caesar's growing power and wish for Brutus to take action.