Who is the Master

In ep 3, On the shooting date between the parents, you see Saeon mother look at an article about the bombing on her phone.

In the very next scene, the Master texts the article to the kidnapper while he was cutting up fish. Obviously, the kidnapper is her real biological son who likes to eat fish  and she controls him.

 LindaSeton:

In ep 3, On the shooting date between the parents, you see Saeon mother look at an article about the bombing on her phone.

In the very next scene, the Master texts the article to the kidnapper while he was cutting up fish. Obviously, the kidnapper is her real biological son who likes to eat fish  and she controls him.

Idk if you've watched the latest episode but we know that whoever pushed hee joo is the one the kidnapper is working with, so it can't be the mom because she wasn't there

#WhenThePhoneRings ep 9 synopsis:

heejoo has lost contact with saeon, and finds out another very shocking fact while searching for his whereabouts.
finally hearing news about saeon, she runs to him…at the same time, she makes a big decision for saeon’s sake. 

 and finally, the unexpected identity of the “master” is revealed…!