CHAIRPERSON
The informer is told he must go inside, and he goes and sits quietly inside, waiting for the other two outside.   He makes no attempt to escape.  The same when he is walking down the road with Dube.  He walks along quite peacefully.  None of this rings true of a person who knows he is an informer.
	It doesn't effect the fact that Dube might believe he is, but merely to strengthen your argument that there is nothing whatsoever to suggest that the deceased was an informer, none of his own behaviour was what one would expect of an informer.