Gathering reference is always an essential first step in my process. I gathered a gazillion different images to find the right mood I was searching for, but eventually filtered them down to the reference board shown below.
Starting with a blockout pass to establish scale, composition and lighting, all of the scene elements slowly evolved from here...
Once the blockout scene felt balanced, I started creating all the modular assets to construct the final scene.
Once all the modular assets were integrated, I created a master material for vertex painting between three different textures each with separate parameters for grunge, damage and water puddles. Then I scattered a ton of decals around the scene for storytelling, visual landmarks and breaking up texture tiling. Foliage and debris were painted using Megascans assets.
I'm constantly watching my lighting values to ensure all surfaces have proper contrast.
For my victim, I created a sleazy looking MetaHuman and imported him into Unreal. I then exported the character meshes out to Maya for mesh tweaks, cleanup, retexturing, and final posing. Then imported everything back into Unreal for final placement and materials.
Fitting my porkpie hat and glasses on the victim's head. What a sleazebag... He probably deserved the crime.