App with a question mark won't delete

Hi, I downloaded Geogebra Classic 6 some time ago from the App Store. At some point a question mark appeared on top of it on the Launchpad and since then I can't find a way to delete it. I tried:

-dragging it to Trash

-holding click over it until it starts shaking and clicking the X

-option + click to remove

And after every attempt nothing happens.

Also, it doesn't show up on "Applications" folder, so I can't remove it from there either.

Any other suggestions? Is there some other way to delete it?