In the latest "Mouse" episode, detective Go Mu Chi (Lee Hee Joon) and police officer Jung Ba Reum (Lee Seung Gi) received a new murder case - and the two are more than fueled to catch the culprit and put behind the bars.

Oh Bong Yi's Grandmother Murdered by the Evil Predator

In "Mouse" Episode 4, another murder case has occured. This time, the victim was Oh Bong Yi's grandmother (Kim Young Ok). The bloody murder shocked everyone, and left them asking how an innocent person die in such a brutal way.

Because of what had happened, detective Go Mu Chi and Jung Ba Reum took the matter in their own hands to search for the serial murdered. They joined forces again to make the work easier, and to bring justice to Oh Bong Yi's grandmother.

READ MORE HERE: Block B's P.O, Lee Hee Joon, & Kyung Soo Jin Join Forces in Upcoming 'Mouse' Episodes

Detective Go Mu Chi and Officer Jung Ba Reum Furiously Search for the Culprit Behind Oh Bong Yi's Grandmother's Death

The two started searching on the places approximate to the incident location. But they were not lucky enough to get evidence. Jung Ba Reum is dedicated to finding the culprit because he still feels guilty of what had happened to Oh Bong Yi's grandmother, if only he had answered her call, there'd still be a chance to save her.

Oh Bong Yi (Park Ju Hyun) is still mourning after she lost her beloved grandmother, she admits that they had a misunderstanding the last time they met but Oh Bong Yi is regretting it. She didn't know that it would be their last memory together. After hearing that Jung Ba Reum was called by her grandmother asking for help before she died, Oh Bong Yi immediately went to where Jung Ba Reum is and started to accuse him for not doing anything.

Meanwhile, Jung Ba Reum was in the hospital and was injured because he tried to look for Oh Bong Yi's grandmother that night but it was too late and the moment he found Oh Bong Yi's grandmother, she was already dead and stabbed by the murderer. He was in deep loss after seeing the old lady covered with blood. The next thing he saw was a man standing behind the door and it was said to be the man behind the killing, Jung Ba Reum immediately chased him, but unfortunately he wasn't able to catch the killer, because the next thing he knew, he was already at the hospital, and found himself crying. He still blamed himself for what had happened to Oh Bong Yi's grandmother.

Doctor Sung Yo Han is the Murderer

Meanwhile, pieces of evidence can be seen throughout the episode 4, doctor Sung Yo Han (Kwon Hwa Woon) is the man behind all the murder cases happening in the city. It was when his mother (Kim Jung Nan) was about to get his clothes for laundry and found out that the whole outfit was covered with blood. She was terrified upon seeing it, and when they are about to eat the dinner together, she just pretends that the blood was from one of his son's patient from the hospital and not from another murder case. It seems that she knew that his son is capable of killing people.

It was also based on the observation that Jung Ba Reum had when he encountered the man during the night when Oh Bong Yi's grandmother was killed.

Now the identity of the killer is being revealed piece by piece. Will detective Go Mu Chi and police officer Jung Ba Reum finally found the evil predator?

Meanwhile, according to Nielsen Korea, "Mouse" episode 4 that aired on March 11 was able to achieve a new high rating, it garnered an average rating of 6.202 percent nationwide.

You May Also Read: Lee Seung Gi's Drama 'Mouse' Sets New Best Viewership Rating Record + Episode 3 Recap

Have you watched the latest episodes of "Mouse"? What can you say about it? Let us know in the comments!

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Written by Shai Collins.