I remember being in like 5th grade or something and being asked by some teacher who noticed I was always reading why I never used any bookmarks even for massive books. I told her they're too easy to lose, and she said "but how do you remember your place? You don't even fold the corners."
I gave her what what must have been a confused or incomprehending look, because she laughed at my expression and asked "no really, how?"
So I just showed her. It's obvious, right? You open the book up, read a bit. Go back if you don't remember this part, skip forward if you do. "Just like with a movie." Except faster, it usually takes just a few seconds.
And that's the age I first learned that not everyone experiences a movie in their head when they read, and that it's actually quite hard for many people to remember the events of books they read after even a few days of not reading.
I mostly bring this up out of surprised confusion that this was new information to the cops. It seems like such an obvious strategy given the experience many had growing up with VHS films that part of me is inclined to doubt it, or think they just wanted an excuse not to do the work.