here is my thought. IF RM did look nervous and worried in the video and LE saw that. Why would they say no foul play? Can they think he looks worried and nervous due to the fact he is leaving and doesn't want to get caught? I can't quote but pretty sure when foreman from arrow was interviewed he said Mr. Mayer was in good manner. That is a big chnge from very nervous and worried!
IMO, I think if she saw that same video when he was not missing, she would not think he was worried and nervous. She could be reading into his facial expressions, because he is missing. She could be looking for clues, as we are looking for clues. I could be wrong, but it is just a thought. His expression could be that he was having a hard time reading the screen or the instructions on the ATM, so he was frowning and straining his eyes. Unless he was wearing contacts or glasses, most people need reading glasses at his age.
JMO