Terrifying movie but majot plot hole
Why couldn't Jennifer Glick's ghost just murder Charles if she was haunting the same house he was hiding in? She was clearly powerful enough to throw around Annie and direct a knife to a specific target. So why not just attack Charles and get it over with.
Was it that there was a special connection with Annie just because she was wearing the cross, that made only Annie susceptible to Jennifer's ghost? That's the only far-fetched explanation I can come up with.