I get emails at work all the time from people who find my email on professional lists. Usually wanting me to try their software or their program. Unsolicited, I consider them to be junk mail.
In this case, after six years, this person apparently found the original text of this thread or more likely (since she has your e-mail address) evidence of the original e-mail you sent to the parole board so knows you were interested in the case. And she is possibly correct that he has been released. The only William Graham currently showing as being held in the Colorado DOC is only 32 years old and won't be eligible for parole till 2043.
If it were me, I would ignore her e-mail. She contacted you and you don't know her. That's reason enough to ignore the e-mail. It's just like a telemarketer calling your home phone. Unsolicited gets ignored.