The nudity shown is in no way explicit, or sexual in any way. It's disturbing footage and it's portrayed that way.

Grainy news footage of people in an institution who are naked or scantily clad. Butts and Vaginas shown.

None shown (that I recall), though see the category below (#4).

One interviewee says the F word

Some people seen smoking.

Because of the nature of the crimes discussed in this movie, it is quite frigtening. The death/disappearance of children is explored at length, and there are a number of scenes where the filmmakers explore abandoned buildings, both daytime and night-time.