It is because he does genuinely believe that Elsa killed Anders! He does not know their love was true!

[Not that Ingo is a particular Detective Berglund fan, but he tends to sympathize with most characters who aren't just outright awful!]

Yes, that too. But you all think that he is dead, so there is certainly no thought in anyone's mind of all that when I appear! It was decade ago! And I suppose I would not see you until much later in any case, or else we would have just had a dragon battle then.