Hackers scan the internet 24x7 looking for vulnerable computers. I've read reports showing that a computer connected to the internet is scanned within a few minutes of being connected. If its not secure, as this one was, then it was almost certainly targeted within minutes. It was probably hacked within the first few days of being turned on. Once they knew it was hers they were probably monitoring it from within round the clock and had those emails before their intended recipient had read them.