Yes, I know that the Boston Marathon bomber caused terrible death, injury, mayhem, and a huge cost for all that was done to find him… But I find in myself a concern for his well-being. I hope he recovers and can provide information as to why/how he and his brother did what they did.
I am against the death penalty. So I hope his time in prison allows for a time to reflect and pray. Hopefully for time to repent and be transformed.
All of us are sinners. All of us are in God’s care.
Love your enemy – Pray for those who persecute you.
“Judge not,” we are told.
“Pray for us sinners,” we pray.
Thus we pray.
For ourselves and for everyone – without exception.
Heart Streams in Dry Land 
Hopefully the pain we feel will awaken us to the pain we cause others and lead us all to compassion and forgiveness.
Sounds like you’ve done a lot of inner work, pilgrim 85. And you point, exactly, to one method which can lead to compassion and forgiveness. This is our task, our calling, one might say. And there are many paths, including Buddhism, which provide methods. The Dalai Lama, at one point, decided to work on compassion. As I recall, he pursued this for at least 10 years.
Thank you for your beautiful comment! May it be so!