This 70s era TV movie featured a college couple where the man killed his girlfriend by shoving her off the roof of a tall downtown city offices building. He had taken her there for an elopement wedding. But he took her up to the roof while they were waiting for the JP to be ready for them. The woman's sister unraveled this "suicide" by observing that the victim was wearing something old, something new, something borrowed, and something blue. This convinced her that her sister had gone to the building to get married, not to commit suicide. This led to a search of her male acquaintances. Sorry, but I have no actor/actress names.
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