STORYTELLING: Research and Ideas For My Script

I have not had any experience in scriptwriting, however, I feel as if I need to set the scene first before I can start any writing so I have an idea of what's going on before I put words with it. 
The first scene will be at the crime scene in the bedroom of the victim with the police and forensics. Maybe they can be talking about the cause of death and the evidence. 

The next scene will be the detective in a room in the police station late at night going over the evidence of the murder. The killer then knocks at the door and says he can help her. I researched how the police deal with people coming in to give evidence about a crime and what the steps are that they follow: 

https://www.nidirect.gov.uk/articles/coming-forward-witness

I also researched what rooms in police stations look like and I am aiming for something like this: 

https://www.pinterest.com/pin/389913280215424707/

https://www.pinterest.com/maggknits/medical/

The photo above is the room I can imagine the detective being in late afternoon looking through the evidence. There is a room in our base room of the Studios that I think I would like to use. I would also like to bring my actors in from outside so I will ask about how to do that. The photo to the right reminds me of the base room in the Studios with the long narrow layout, therefore, I may use parts of the base room showing the man walking to the room the detective is in. 

http://science.howstuffworks.com/csi.htm

(Above) The next thing I researched was how crime scene investigations work. For example, who is at the scene and how long the scene is a crime scene for before things go back to normal. This is because when my characters talk about the crime scene I want their facts to be correct.