Here is the solitary quote from which this entire "activity" thing is coming:
"We have information from that video that again gives us an indication not only of the direction (of her travel) but the activities that have taken place from where that video shows,"
That's it. It is ambiguous at best whether or not any activity is even shown let alone that something definitely happened. His responses weren't scripted, he is reacting like anybody would and says things that don't necessarily have any meaning at all in order to placate the reporters.
As for the name of the person she was with, LE hasn't released any names at all, so I am failing to understand why people keep coming back to quesioning the alley partner.