What were they looking for? BB

I got a tip for a 40k BB/727 in a 68 Newport. Engine was complete Thursday when I looked at it. Kinda hidden at the pull a part. I talked to a guy about pulling it. Went back today and got the 8 3/4 and was going to make engine pulling arrangements. Well you know the story... Someone started pulling stuff. Carb and cut the linkage off.

Here is the question...why did they pull the valve covers and then leave it. What were they looking for? Trying to get educated on BB.