I don't think they are suspects because they are odd. It's a culmination of many things:
1- 3 page dramatic ('don't try to grow a brain John') ransom note written on Patsy's own notepad and with a pen from the home and pen and notepad were replaced back in their spots (also practice note was written). Left on back stairs that PR used. Anything in the house would have been Patsy's, it was her house.
2- lawyered up immediately and separate lawyers for each parent IMO, they did the right thing. They knew they were suspects, and innocent people have everything to lose when the police have only them in their sights.
3- JR was overheard getting his jet ready to fly to Atlanta right after her body was found Overheard by who? I thought on the A&E special they said that it wasn't true he was planning on leaving. Since they already had a fight planned, I'm sure he had to notify his pilot of any changes.
4- parents wouldn't be interviewed separately by LE I wouldn't be either if I knew that the police were trying to pin my child's murder on my dh, myself of my other child.
5- parents wouldn't allow BR to be interviewed for like 2 years He was 9, no other explanation needed.
6- parents didn't react when ransom time for call came and went What does that mean? They didn't react the way someone else would have?
7- story was BR slept through everything but now he tells us, on DR P, he was awake in his bed...also might be heard on 911 call I don't know why this matters unless you really believe that he murdered her.
8- story was JBR fell asleep in car and was carried to bed yet pineapple was found undigested in stomach and bowl of pineapple on table A 6 year old child is capable of waking up, going into the kitchen and getting themself a snack. And I know my child would have just left it there and not cleaned it up when finished.
9- what have they done to find killer? wrote book about how they were wronged Isn't that the police's job?
10- JR moved body and removed duct tape, contaminated crime scene The crime scene (the house) was contaminated from the very beginning. A father grabbing his child and picking her up when found in that condition doesn't seem at all unusual. I could see my dh doing the same thing.
11- parents left BR in his room alone when supposed kidnapers had been in the home Why did they think the kidnappers were still in the home? Did they say that?
12- parents went on talk show shortly after burying her but way before being interviewed by LE The same LE who already assigned guilt to them.
13- PR referred to her constantly as 'that child' I didn't know her personally, is that how she always referred to her?
I am sure there is more. But there was enough for GJ to indict.