Yes...and it's worthy to note that it's obvious the detectives didn't give anything to the parents but kindness..per their own words.
Immaterial. The detectives are professionals; their task was finding Danielle and the culprit behind her abduction (now murder).
Until she was found, it would be counterproductive to the potential of a good outcome to investigate or charge the parents. Even if they violated the law (with drug use, for example), with the DA fighting for his career in Tuesday's primary, you can bet he's is going to treat this NATIONAL case carefully so he can ride it to reelection.
Their behavior may be whitewashed by the media firestorm they were able to bring so close to this contentious reelection bid. If the case is settled, we may never know all the facts. You can be sure we'll be seeing a movie-of-the-week and book-of-the-month though.