I have to respectfully add my 2 cents. Child *advertiser censored*/trafficking cases are very, very complicated, particularly with regards to the computer forensics. Keep in mind - every picture depicts a crime, and there's always the hope that the child depicted is alive and can be rescued. These investigations often involve the FBI, ICE, Interpol, etc. Its a great thing to get a local guy with kiddie *advertiser censored* off the streets - but LE will be meticulously careful to not do anything to interfere with corollary investigations, particularly ones to capture the abusers who record and distribute the filth.
Also this isn't a popular stance, but being accused of having kiddie *advertiser censored* is probably one of the most damaging accusations to ones reputation. Before LE arrests someone for it, they're going to want to make sure the computer wasn't hacked, there wasn't a virus. That takes some time to track IP addresses, file originations, etc. It's not a quick process. But LE can't and shouldn't arrest someone without fully investigating - imagine if your husband, son, dad's computer had a virus, and without investigating they were hauled in to the police station?
Of course hindsight is 20/20, and we'd all be a lot safer if future murderers were born with it marked on their faces.