Reality above Entertainment?

This drama is absolutely wonderful. The casts are great, the acting is great (so far Episode 24) and lastly, the story is great. For all you people out there that have lost someone, whether it's your mum, dad, brother, sister, anyone.... Please watch this drama. I'm not telling you to watch it because the characters in this drama also have lost someone and I want to remind you of your pain but because I want to help you cope with it. I believe this drama really helps with it, friendship and a hint of romance will leave you memorized. 

The reason I created this Discussion was (despite how much I'm enjoying this drama): Is this drama realistic. You're probably thinking, yes it's realistic, it has things that the modern world today has well let's discuss. Also, please feel free to express your opinions about my ideas, and also please respect other peoples opinions and ideas.

This is the only question I can think of right now so here it is:

Isn't it possible to get DNA from Yu Na's clothes? 

Here is my argument, watching this drama you can see not only from Jang Do Han's point of view when the scrub kills Yu Na, but also the scrub's point of view himself. This drama is supposedly set in 2016, whilst watching episodes 1-24 I realize that this has a lot of potential because it's realistic, I mean come on, those guns and physical scars, woot woot!. Anyways what I wanted to say was, you can clearly see that the scrub pushed Yu Na to her death, so why don't the police or her mother Jo Soo Ji be smart and ask for DNA testing? seriously... The bad guys later on get DNA testing on hair samples, which in reality is more complex because for all you know, you could have a cat and he's been sleeping with you ( not in the wrong way for all you perverts out there ) and someone gets a hair off your head and takes it for DNA testing, for all they know it could be a cat's hair and not yours. But this is fingerprints, FINGER PRINTS, FIN-GER-PRINTS. Everyone in this world has a unique finger print, so the only way for this DNA testing to go wrong is if he used someone else's hands ( see I said hands because you can see that the scrub pushed her using his hands nnot just one finger ). Like if you take Yu Na's clothes for DNA testing, you will likely find 5 finger prints, get a warrant for testing the scrub's finger prints and there you have it, crime solved, also the clip from the camera helps as well. Now I know a lot of you people may argue that the scrub could say : ' Oh well I volunteered to help the kindergarten that's how my finger prints got there'. You can always check the ripped paper. From the drama we know that Yu Na made a drawing (sketch) of her dad and she wanted to send this to him in heaven ( feel free to correct me if I'm wrong ) that's why she asked the scrub for somewhere she can reach the sky or something ( Feel free to correct me once again ). This drama is so realistic to the point where it gives me chills, but the fact that her Police mother let alone the entire police force couldn't think of this simple plan to scan Yu Na's clothes and the ripped paper for the scrub's DNA, is a little bit oblivious.

Anyways this is it, please feel free to correct me if I'm wrong, (politely if I may ask). Also, feel free to give me your inputs and ideas. 

Like i said in other posts, he covered the entire base when he was interrogated. Even the remoted share of evidence was destroyed by his testemony, who was plausible and credible. In this case, DNA doesnt do much. Its a very difficult case to make an arrest... With a good lawyer, Si Wan would walk free.

The only thing that counts as concrete evidence is a Witness to the scene. And that witness has to be credible, because the defense would discredit the testimony.  

This is a very interesting view. For me, this drama seems to be the opposite of reality, the way interrogations happen, hostage situations, police protocols etc. The prosecutor can't just barge into an interrogation randomly; if someone assaults a witness, they'd be thrown out of the room instantly (whether their phone is ringing or not), police surrounds the perpetrator and hostage to prevent them from escaping, etc. 

All of the above are only my opinion. Just thought I'd share my (maybe unpopular) opinion.