Wow. Some pretty crap attitudes on this thread 
OP, this was the group that I went through with my penpals: Human Writes - I don't have time to look at their site now (long day tomorrow + early start, I should be in bed!) but if you contact them I'm sure they'll have some good ideas of where you can go to get some support with this.
FWIW what you are feeling (compassion, empathy, all that stuff lacking elsewhere on this thread
) are entirely normal. It's not unusual for penpals to become emotionally involved - I know some people travel over to the US to meet their penpals etc (for friendship, not marriage etc
).
For everyone else, this is from the front page of HW:
"More than 3400 people are condemned to death in the United States, facing many years on Death Row before they are executed. Many of them have been there for ten years or more and may be given several execution dates, sometimes coming within hours or even minutes of execution before the final one.
Many living under sentence of death have severe learning disabilities or are mentally ill; some have had an abusive childhood and a high proportion have had very poor legal representation. We also remember that capital punishment in the US has famously been defined "Those without the capital get the punishment".
Living conditions on Death Row in many states are harsh and dehumanising. It is not unusual for people to be locked up for 23 hours a day or to suffer sensory deprivation. Many of the prisoners are abandoned by their families and friends and some have no contact whatsoever with the outside world. Receiving letters can make a huge difference to their quality of life; prisoners speak of us as their sunshine or their window on the world. Above all, they value being able to have a normal conversation with someone and the feeling that someone cares."