I do remember one case where a child disappeared,and the parents were never suspects. It happened in Miami in the 50's, and it was a little girl,aged about 5. Cannot recall names,but I am going to look.
The child was sleping in a bedroom at the front/side of the house. Her bedroom window was left open ( no A/C), and the window had a screen in it. She was put to bed, and found to be missing in the morning. No one heard anything at all. The scren on the window was pushed out.
IIRC, I think she was an only child. But the only other people there were her parents, and,IIRC they both took and passed LDTs.
I read about the case when we lived in Miami, I think it was an anniversary of her disappearance. Parents never really susects. Why I do not know. Maybe the LDTs ? Anyway, she was never found. If I get a chance I will try to access the Miami Herald archives to get more info. I did some research on the case when we lived there,but no longer have my notes...
I suppose that technically one could say that Sierra Lamar's mother and her mother's BF were not considred to be suspects at the beginning of her case. I think it was mentioned that they had alibis. And I'm sure that LE pinged their cells right away...Later on, another LEO in the case said something different, so IDK...
Just some thoughts...and MOO