As a criminal defense lawyer, most sexual offenders I have represented have intermittent and considerable empathy, but a few are psychopaths with no conscience or (as to child sexual abuse) with a feeling that they are enriching the lives of their young victims, as with a rite of passage or initiation in their twisted minds. Violent sexual offenders have a reservoir of rage which rears its head and trumps all empathy in the act of assault, though there may sometimes  be remorse later. Also important is not to confuse nostalgia or sentimentality with real empathy. Just my experiences as a lawyer -- not expert and largely anecdotal -- but I will say that contrary to a strong current of conventional wisdom, some treatment appparently works to send child sexual impulses into remission for sustained periods, even for the lifetime of the offender. Clinical practitioners at  Johns Hopkins University in Maryland  have had  success in this. http://www.livescience.com/17519-treating-pedophiles-therapy-challenge.html 

Many thanks for your comment! We found it useful to bring the voice of the offenders to listening; not to defend or excuse what they did but to study how they use or misuse language and other human qualities - and they do it, surprisingly, very skilfully.This permits a more encompassing view of these people as they are not only sex offenders but traumatized, in early years often violated and exposed to violence, trying to make something of a life that started from very disturbed conditions. And one can begin to hear it, not only to diagnose it. This, I hope, increases chances of dialogue with them and then chances of therapy.

However, I hope that other CA-studies will follow.

Best

Michael