When one flips a light switch there is an immediate appearance of light. The cause and effect is obvious. If someone steals money and the next week he is caught and jailed - we say justice is done.
However if someone robbed a bank as a twenty year old. And has lived as model
citizen in his community for 30 years, happily married and has family - there
is a feeling that somehow the past should be forgotten. (There is a bit more problem of a concentration guard who killed and tortured hundreds of people - we don't forgive so fast even if he has lived an exemplary life for 40 years.)
If a person committed crimes but he was never caught and then he died - should the discovery of his criminal past be mentioned or allowed to be forgotten.
All this is leading up to the question of sexual abuse. It is not rare but rather typical that there is a significant passage of time between the crime and the complaint and punishment. This is primarily due to the psychological trauma resulting from the crime.
We typically hear, "Why did it take so long before they complained?" "What good is it to put an 80 year old grandfather in jail for raping kids when he was 25 years old." There is much that can be said to explain the psychodynamics but that is really not relevant to the question.
It is generally perceived that by having a delay of years or decades between the crime and reporting and punishment - is inappropriate or even immoral. However there is no such idea in halacha.
What about the claim that the person has done teshuva and thus doesn't have to be further punished? The simple answer is that teshuva is not complete without punishment. There is no concept that teshuva erases a crime - whether it is theft or murder.
In sum, a passage of time - no matter how long between crime and reporting - has absolutely no relevance in halacha. If you have any sources that contradict this conclusion I would appreciate being enlightened.