Why can't I kill apps with my lifeproof case on my iPhone 5c?

[iMore Question]

The home button works, and I can get Siri if I hold it down, but when I tap it twice I can't activate the fast app switcher anymore.
Any suggestions or other ways of killing apps on the iPhone without having to remove my case regularly?

 

[Reparkable]

I don't understand what your case has to do with clearing apps.

If you say your home button works then just click it twice quickly and the recently used apps should show