At the end of episode 13 of CODE GEASS R2, Shirley was seen dead. It caused a devastating effects on Lelouch since he loves her. It was unknown what or who caused it. It was said that she was shot because of the looks on her wound.

Suspects

Shirley herself (suicide):-

Argument for:-

• She was holding a gun
• She didn’t tell Lelouch who killed her
• She stopped Lelouch from calling help
• She couldn’t accept the fact that Lelouch is Zero

Argument against:-

Kururagi Suzaku

Argument for:-

• He had full control of the building
• He was most likely to be inside the building

Argument against:-

• He has nothing against Shirley
• He won’t regain anything by killing her
• He promised to kill Zero not anyone related to him

Rolo Lamperouge

Arguments for:-

• He’s obsessed with Lelouch and will let nothing interfere with their relationship
• He made an unpleasant face as Nunnaly’s name was mentioned
• He knows that Lelouch loves Nunnaly more than him
• He activated his Geass before the incident happened
• He wasn’t thinking of the consequences of his relationship with Lelouch because of jealousy
• It’s not a detective anime (e.g. Case Closed) so the producer probably didn’t care how the wound looks like so she might got shot from either way
• the locket that was given to him by Lelouch was shown after he activated his Geass which means it gives a huge impact if he killed Shirley
• His “mask” which represents loyalty and honesty fell

Arguments against:-

• He won’t let Lelouch get hurt both physically and emotionally
• If Lelouch knew he murdered Shirley, the relationship between Rolo and Lelouch won’t be good
• He might activate his Geass for a different reason
• Shirley’s wound look as if she was shot from the back because the skin burst from the abdomen

Jeremiah (Orange)

Arguments for:-

• He might used the ’switch sides’ confession just to loosen up the situation
• He might decided to defeat Zero emotionally by killing his loved ones

Arguments against:-

• Maybe he was honestly loyal to Marianne
• He was injured

Anya

Arguments for:-

• She might wanted to take revenge for what Lelouch did in the past since she knew her since he was a prince
• She knows Shirley
• She seems suspicious
• her location was unknown at that time

Arguments against:-

• She was probably fighting Todou’s group in China
• Somehow it’s unlikely

Some random soldier

Arguments for:-

• urmm..well, i don’t know maybe he accidentally did it

Arguments against:-

• It doesn’t seem right for a minor character to kill an important character which causes a huge impact on the show
• They’re not suppose to kill innocent civilians

A new important character:-

• it might be

Discuss, suggest anymore possibilities.