Luigi
You don't have twenty minutes to spare, but you manage to get a few details. The man is clean; a few speeding tickets but nothing big. Finished high school with mediocre grades, divorced one time...nothing really especially interesting about him. Just the wrong place at the wrong time.
The Cluemaster is a two-bit Riddler-knockoff who leaves deliberate clues at crime scenes due to a mental compulsion. He also has a daughter.
Katherine Walker
There really isn't much more that you can tell without further equipment. You find some loose hair inside the book, but that's about it.