Why does Mark visit Waldo?

What is the relationship between Waldo and Laura?

Who does Waldo believe killed Laura?

How did Laura meet Waldo and Shelby, the two men in her life?

Why does Waldo believe that Shelby is not good enough for Laura?

During his time at her apartment, what type of feelings does Mark develop for Laura?

When Laura returns, what do the characters discover really happened?

Why does Shelby try to protect Laura?

Who actually killed Diane and why?

Where was the gun hidden?