Continuity mistake: In the beginning of the film where Charlie watches Dandridge and Cole move the coffin into their house, there is a close-up shot of Amy removing her blouse. The film then cuts to a close-up again of Charlie and in the background Amy's blouse is still on (probably only visible in the widescreen version of the film). (00:05:20)
Continuity mistake: When Jerry has Charley pinned to the cracked bedroom wall by his neck, he suddenly drags him over to the window a few feet away - which is nailed securely to the frame - and lifts it up effortlessly. Next, we see Charley looking over to his right side, but now he's back up against the cracked wall in this shot, not a window. (00:29:50)
Answer: Peter's odd behavior at Jerry's house made Jerry suspicious. When he discovers the shard of the mirror on the ground he finds out why Peter was spooked: Jerry doesn't cast a reflection. Jerry then decided that Charley's friends must be dealt with. In Ed, Jerry sees something which would lead him to believe Ed would make a good servant. Jerry turns Ed into a vampire and sets him against Peter while he himself deals with Charley and Amy.
BaconIsMyBFF