In Chapter Five of Inglourious Basterds, Revenge of the Giant Face, Colonel Hans Landa strangles Bridget von Hammersmark to death with his own hands immediately after placing her at the scene of the shootout at La Louisiane pub. This violence is unnecessary for performing his duty since the cinema is packed with the German military and security. It seems to be personal revenge and it surely cannot be patriotic feelings as by that time Landa had already been contemplating defection. Also, the only link between Landa and Bridget is Major Hellstrom, who had been shadowing the actress at La Louisiane and quite possibly had been assigned this duty by Landa himself.
It could be that he felt responsible for getting his protege killed, but I think an outburst like that would require more intimate feelings. I think Landa wanted closure for the death of his beloved one.
Unfortunately, the only time Landa and Hellstrom meet in the movie (in the restaurant where Shosanna meets Goebbels) we cannot see their faces.
Were Landa and Hellstrom lovers? Is there any proof? Why would he kill her in such an intimate fashion otherwise?