Title: AMAZING SPIDER-MAN#277 by Tom DeFalco and Ron Frenz
Synopsis: Scourge disguises himself as a police guard while listening to a news broadcast of the massacre. He enters the prison where Flash Thompson, erroneously believed to be the Hobgoblin is being held, and attempts to kill himself. Spider-Man rescues Flash but Scourge gets away by opening the cells and announcing that he is Scourge. He tells the the inmates that he'll kill them if they don't get in Spider-Man's way. He escapes to the roof top just as the Wraith is breaking in. He tells the Wraith, "I am called the Scourge. Remember my name and die!", then guns down the Wraith and abandons his mask, making his getaway.
Is it a key part of the overall Scourge storyline? Well it turns out that this is the first appearance of a new Scourge, but that might not have been the writer's intent. That this is a different Scourge is confirmed by the fact that he hears a different news broadcast than the original regarding the massacre. Master Universe Masters Edition also confirms it's a different person.
Is it part of the main story in this issue? The attempt on Flash Thompson definitely is the main plot of the issue. The actual hit on the Wraith is more incidental, with the Wraith going on a revenge trip and being at the wrong place at the wrong time.
Comments: This issue came out the same day as the massacre issue of Captain America. However, the announcement of the massacre at the beginning of the story means it takes place right after.