SketchUp can easily incorporate into an investigators existing workflow. An investigator can document a crime scene with traditional techniques like photography, hand-drawn sketching and measuring, Total Station/LTI Laser surveying. The data can then be brought into a CAD program like CadZone or MapScenes to create a traditional 2D diagram. That diagram can then be exported into SketchUp where that flat 2D diagram can be built up into a scaled and textured 3d model.
This model can be used to show a walkthrough animation giving perspective to a jury that otherwise would not be possible. Photorealistic renderings can be generated to depict accurate representations of a crime scene. But the best part is that this powerful program is free.