I used this tactic when house hunting a couple of years ago. The market in DC / NOVA can be competitive sometimes, so when I was viewing a house with a lot of interest (which means you often see other buyers there), I would always walk in as if in mid conversation with the realtor:
"Wow, they did a really good job on the paint down here. You can even see the bullet holes. Poor man".
"So this is the famous Smith Murder House, eh? It looks so innocuous ".
Worked at least twice too!