The Ninja Epidemic

So there's a corpse in the house and your fingerprints are everywhere. This is a no brainer for you. You need to wipe the area down. You don't need any signs pointing to you, because nobody is going to believe the ninja story.

You get a cloth from the bathroom and begin wiping down everything you touched, everything you might have touched, and everything that you could have touched. You're not taking any chances here.

You've been wiping up evidence for a good half-hour. You're almost done, you realise with relief. Just as you start to wipe down the last spot of the wall that you're pretty sure you brushed up against, you hear the front door open.

"Harry!" You hear his mom call up the stairs. "Harry, are you feeling any better, honey?" You hear her start to walk up the stairs.

Shit. How the hell are you going to get out of this one?

Well...?