The child is 5?? Okay that's too young to know how to run away... But how did the child know how to open the window in the first place... He's only 5... Lol. I thought the child was like... 7/8 haha...
Let's change it to the friend hiro. She searched the boys room so she had a chance to grab her phone. She searched the toilet even though she had been there when the boy was missing... The boy was probably in the tree house where she hid him. She could have known about her friends husbands disappearance and death and that her friend would definitely pay the ransom this time so she made use of this fact.