In spite of what you see on TV, it's not up to a victim to decide whether or not to press criminal charges in the end. That's up to the attorney general usually.
Though police do often drop criminal charges if the victim is uncooperative.
Here's a recent example: a friend of mine was raped and strangled to death last month. They caught her alleged murderer last week. When the media got a hold of it, they found out that he had been accused of rape and attempted strangulation five years ago, but police decided not to press charges because the victim wanted to let it drop.
So yeah, it happens; it's just a spectacularly bad idea for the police to do it. If they hadn't declined to file charges, my friend and another murder victim would probably still be alive today.
If all the relevant material is "spilled" in a civil trial that the victim is pursuing against someone else, the victim's cooperation in the criminal case is less likely to be needed.
Here's a recent example: a friend of mine was raped and strangled to death last month. They caught her alleged murderer last week. When the media got a hold of it, they found out that he had been accused of rape and attempted strangulation five years ago, but police decided not to press charges because the victim wanted to let it drop.
So yeah, it happens; it's just a spectacularly bad idea for the police to do it. If they hadn't declined to file charges, my friend and another murder victim would probably still be alive today.
Source: https://www.dallasnews.com/news/crime/2017/05/26/man-killed-...