I wonder if the piece of paper was a copy of something, like a picture or an email? I think this person thinks they had a very good reason to kill Liz but everyone else will be shocked this is the reason she was killed. Makes me wonder if it's something work related, did someone think Liz got them fired or did she get a promotion over someone else? I think someone else mentioned it but on dateline I saw a case where a woman was killed in her home by a former employee who had been stealing from the store they worked at. Or in her personal life did someone think Liz was having an affair with their husband?( I don't think she was) But could she have had a male friend or coworker with a crazy wife who thought there was more going on? ETA-I agree with everyone up thread who thinks she was killed by a woman.