I watched this clip a couple of months ago. He comes across as very balanced and logical and his theories are that she either let someone into her house on the Wed evening, they had a chat then left or someone she knew picked her up on her way to work the next day. In both scenarios he thinks it was a lover or ex, who she may have rejected, who became obsessed and stalked her - and he believes that alley man is the culprit. Quite straightforward and mainstream theories. Except the police and some WS members believe he had assistance from friends/associates.
How does your theory differ?