Iam trying to delete an image file but its giving error that call to a member function delete() on string.

This is my code:

public function destroy($id)    {            $element = Element::find($id);        $destination = 'public/images/'.$element->imagen;        if(File::exists($destination)){            File::delete($destination);        }        $destination->delete();        return redirect()->route('elements.index');    }    }

What are the points we should remember while working on APIs ?