Cannot delete app/directory/file in Finder
I tried to update WhatRoute but something went wrong. I reloaded the Update and that worked fine, app does work.
However, since that time I have a file in my trash called "WhatRoute.app" that cannot be deleted. The Finder says "cannot be deleted because it is in use". Activity monitor shows nothing. Restarted several times, also tried secure mode but nothing helped.
Tried to use Terminal using "sudo rm .../WhatRoute.app" but get an error message stating this was a directory that cannot be deleted.
So what is it now? directory or app in use? And how can I get rid of it?
Please help!
iMac with Retina 5K display, OS X El Capitan (10.11.6)