Just who decides whether serious child porn case is in state or federal system?

I kind of know the answer to the question in the title of this post (as explained below), but this is still the inquisitive reaction I often have after reading about a state child porn sentencing decision like this one reported today out of Pennsylvania:

Calling him a danger to the community who showed no remorse, a Northampton County judge handed down a state prison sentence Friday to a Nazareth man who had child pornography and sent inappropriate text messages to a 12-year-old girl in which he said he wanted to make her feel “warm and cozy.”

Christopher M. Rothrock, 46, was sentenced to 21 months to 7 years in prison by county Judge Stephen Baratta. In handing down his sentence, Baratta said he would be “afraid for the community” unless Rothrock served time in state prison.

Rothrock was reported to police in 2011 by the girl’s parents.  Police said they found 25 texts from Rothrock to the girl, saying he wanted to massage her and asking for photos of her exposed stomach, court records state. Police said they also found thousands of child pornography images on Rothrock’s computer.

In September, Rothrock pleaded guilty to five counts of possessing child pornography and one count of criminal solicitation for the text messages he sent to the girl. Northampton County Assistant District Attorney Patricia Broscius testified Friday that the victim and her mother are “extremely hurt, extremely angry” by Rothrock’s actions. “The bottom line is he’s dangerous and he needs intensive treatment,” Broscius said. “He had no remorse, no insight, no empathy for what happened.”

In a pre-sentence report read aloud Friday by Baratta, Rothrock said he had been viewing child pornography for 20 years and didn’t believe it was a crime unless he was selling or distributing the images. He also told authorities he didn’t believe pornographic images of children over the age 10 were considered child pornography.  Baratta noted that Rothrock stopped going to sex offender treatments after Rothrock said he could no longer afford to pay for therapy.

Though not perfectly clear from this story, it appears that the defendant here (1) may have already had a conviction of some sort that got him into sex offender treatment, and (2) had sent numerous sexual texts to a 12-year-old, and (3) had a massive and long-standing collection of child pornography.  Add up these facts in the federal system, and the defendant here would likely be looking at decades in the federal prison system.  But in state court this guy, deemed by the sentencing judge as dangerous and with no remorse, could be free in less than two years.

My understanding is that state and federal investigative authorities and prosecutors are ultimately the persons who decide whether and when a case will be brought in federal or state court when both jurisdictions have authority.  But, as highlighted by this story (and so many others in this area), the sentencing consequences of child porn crimes will often depend a lot more on this (hidden and unreviewable) state/federal prosecutorial decision than any other facts or factors.