Laura/WMG

The second half of the movie is an extended dream sequence.
Here we have a detective investigating a murder, and finding himself becoming alarmingly attracted to the victim. He faces the problems that not only does she already have two strong male presences in her life -- her fiance and her mentor -- but she is, of course, stone cold dead. Then he falls asleep in her home, in front of a painting of her...and when he wakes up he immediately discovers she's still alive, and investigating the attempted murder further he manages to reveal that both of the men in her life are unworthy of her, and finally he wins her for himself. Our verdict: just a far-fetched dream.

Detective Mark McPherson is the same person as the detective from Where the Sidewalk Ends.
Plays off the above theory. They are both New York City cops named Mark. Both are played by Dana Andrews. Both have a tendency to get violent with criminals. Mark Dixon from Where the Sidewalk Ends is the same character, now ten years later and a little more jaded and self-destructive after becoming obsessed with the dead Laura. Mark changed his last name to McPherson to avoid association with his criminal father, but sometime between the movies he was outed and went back to using his real name. He meets a woman with a strong resemblance to Laura and falls for her. Since he never got over his obsession, he spends the movie trying to help her and facing the consequences of what that one case has done to his life.