This would creep me out! I've known several criminals (before and after incarceration). All of them have a "Poor Me" story about how they were wronged, not loved enough as a kid, set-up, etc. Even if it is actually true (and often, it isn't), there is a huge difference in the way they think, reason, and emote.
See, we ALL have sad stories, have been wronged, made mistakes, etc. The difference with these folks is that they don't take responsibility for their actions ...
Where you and I would think about the consequences and who might be hurt (ie. morals, values, human decency) - they don't. They think about how they will benefit, if they can get away with it, what their story is if they don't, etc.
Where you and I would say, "Wow. That was the wrong choice!" - they don't. They're busy being "hurt" and angry, even though they did wrong. They see themselves as the victim, even as they are hurting you! They will tell you how the person they robbed/raped/killed/etc. did them wrong, deserved what they got, or brought it upon themselves. They will try to garner sympathy and play up how bad they have, how badly they're being treated because of what happened, etc.
Where you and I would ask, "How can I fix this?" and "How do I avoid making this mistake again?" - They. Do. Not .... ever. They will do it again in a heartbeat if they think they can get away with it.
When a prisoner reaches out like this, it is another act of inappropriately crossing boundaries. It's a clear sign that they don't care how the other person (YOU) feels, otherwise, they would contact someone who WANTS contact. This person is fishing for someone to suck into their sob story; some one they can use (eg. for money, comfort items, personal contact, a place to stay when they get out, etc.).
I've seen this several times and it upsets me - a LOT. People stop thinking about the victims and the fact that these criminals are not taking responsibility for their actions. Spending time against their will in a prison that has better internet, food, education, libraries, work out equipment, and health care than I have is NOT paying a debt to society. Taking responsibility would spring from their understanding that they really DID do the wrong thing and their desire to fix it. That, is very, VERY rare and those folks do NOT make unwanted contact.
Personally, I would contact the prison, tell them that you received unwanted contact, and that you don't want it to happen again.