I understand the pressure one can feel when a friend is accused and then convicted of a serious crime. There is the pull to stand by the friend when times are worst, and as the article points out, if you know the friend is going to prison for at least 15 years regardless of what you say, you might feel you can have it both ways, being a good friend while still having get punished and unable to hurt civilians for a long time. Still…
About 20 years ago a former student, who had become a very successful professional and a friend, was arrested and then convicted of sexual abuse of children. My colleagues and I were shocked (we were all psychologists, and had no inkling he was capable of this) and heartbroken (we were also close to his wife and knew his children).
He asked me to write the court a letter on his behalf, with the aim of reducing, not eliminating, his years in prison. It was a painful, but not difficult decision to decline.