On the Leaky Cauldron quotes widget, I noticed this in a quote from Voldemort:
Come, Wormtail, one more death and our path to Harry Potter is clear. He says it in the first chapter of Goblet of Fire, when Frank Bryce is listening at the door.
At the lexicon, they have this to say:
And which death is this? Who is left to murder for the plan to happen? Several more people do die, of course, including Barty Crouch Sr., but none of these deaths were really part of the initial plan. It is very likely that this bit of text is a relic of the rewrite Rowling did part way through writing this book. Perhaps in the earlier draft, Wormtail would have had to murder the teacher that Barty Crouch Jr. would impersonate. As it stands, there is no other murder in the plan, and this text is an error. (Text quoted from
here.)
With the introduction of the horcuxes in Half-Blood Prince, this quote could take on a different meaning. Voldemort may want to go after Harry with all his horcruxes made. Dumbledore suggests that Nagini may be one - perhaps this is the point at which Voldemort makes his last horcrux. This might explain why he kills Frank, rather than Obliviates him. Although Voldemort's not one to worry about a dead Muggle, he might have known that the strange death of the gardener of Voldemort's father's house would attract Dumbledore's attention - which it does. Whereas no one would have noticed a slightly-dazed old man.
Sound plausible?