The Lodger

Using "The Avenger" murders as a backdrop, The Lodger is a film that delves into the power conflicts that result from love.  The best example is the jealousy that Joe feels towards the Lodger.  Through various scenes in the film, Joe is shown to have to a desire to possess/control Daisy.  However, in the presence of the Lodger, he feels that his control is slowing slipping away.
An example of this shift in power and Joe's attempt to keep control is the scene where he confronts Daisy and the Lodger in the streets and Daisy chooses the Lodger over him.  As Joe sits dejected on the bench, the film uses a high level framing to signify that he has finally lost control (1:00:10).  At that moment, he feels powerless in comparison to the Lodger.
However, as he stares at the water's reflection, he pieces together the supposed clues that point to the Lodger being the Avenger (1:00:30).  The low angle of framing and the fact that the water is beneath him points to the control being shifted over to Joe again.  He can use the assumption that the Lodger is the Avenger to gain back Daisy.  Once he realizes that he has control again, he stands up and the height of his figure takes up the whole screen (1:01:16).  The imposing figure shows the power he has over the Lodger and Daisy again.
The struggle between Joe as Daisy's lover against the Lodger is just as important as the struggle between Joe as a detective against the Avenger.  In the end, he may have won against the Avenger, but he lost control of Daisy because of the very desire to control her.