Ruby Chipmunk remove object from space

Question

So I'm writing a platforming game with Ruby, Gosu (ruby and C++ library for handling images, windows and other game-related things) and Chipmunk (physics library for ruby and C++) and I want to delete an enemy. This is the code I used to do so:

@space.remove_shape(enemy.shape)
@enemies.delete enemy

However the collision still happens with an empty space, so I assume I've removed the wrong thing or failed to remove the right thing.
Sorry if this is a really obvious question because I'm new to all of these things.