I don't have a clue what actually happened in the case. I think the reason it has maintained a high profile for so long is because there are a lot of people, supposedly normal people, who are attracted to young girls. If this were the exact same case, but there were only photos of the young lady in normal, attractive but demure clothing appropriate for her age, the case would never have gotten beyond regional coverage. I think a lot of the coverage, particularly on the "news magazine" shows that were so popular then, was because there was footage of the girl that was titillating to a lot of the audience, but they could look at it and go tsk, tsk, what terrible parents, instead of admitting they were excited by the pictures.
There are other factors, particularly the parents being rich and well-known, but the primary reason for the extensive coverage was the large number of photos and videos available of the young girl.