This article has the best information to date about the Galloway Ridge incident described in this downwhen post.
Seven years ago, Barbara Clark pleaded guilty to stealing more than $5,000 from a 90-year-old man at the Durham retirement community where she worked.
A judge gave her a suspended sentence and ordered Clark not to work anywhere she would have access to elderly people's property or possessions for three years.
On Thursday, Clark was charged with first-degree murder, accused of fatally beating a 92-year-old woman who had hired her as a housekeeper. The woman had asked Clark to come to her Fearrington Village retirement center apartment to discuss stolen checks.
There are more articles here, here, and here. (added here.) (12/8 Investigators: Financial Problems Spurred Maid to Attack Elderly Women -- that's no damned excuse.)
A little research might have kept her from being hired in the first place, but I don't think there was anything in her past that would have predicted that Clark would have become a killer when confronted. You want to give people a break, give them a second chance, give them the benefit of the doubt. Then something like this comes along...