Well in that case, he certainly knew where the cookies were. He knew how to get them! So he may have come back, was able to get in, and... yes, he took the cookies! And, he definitely could've been here as well as eating the cookies from Catherine's room because... well because he's Cookie Monster! He'll take all the cookies he can find. Aaaand he knew ours were here as well! Since they happened at different times, he easily could've done both.
Actually, I was here with Will when he was setting it up, and I saw him turn it on. I checked it with him, so he is definitely in the clear with that! After all... you're the one who turned it off, Ed. Maybe you purposely turned it off so you could help Cookie get the cookies!
Ahh, hehe, and great firm Richard is with!