FBI ARA tells Poor Twin he found that half of the photo and shows her a picture of the dead man. Poor Twin helpfully -- for me -- flashes back to the man who she killed in self-defense in the pilot, the one whose body she hid in the trunk and whose phone she kept as protection and which the NEW hitman was trying to purloin from her (phew) because the phone could link the man to whomever hired him (double phew), and: it's the same dude. And the phone is missing now. This means, in Clue parlance, that whoever's got the phone wanted to shoot the girl.