Alley: Crime Scene
Don't worry that you won't be allowed to look inside the cab right away, because we'll deal with this problem once the cab has been successfully towed to the CSI garage. For now, you should click on the cab. Wait for the game to zoom in the view on the dead driver (near the hood). Click on him and choose Digital SLR Camera from the inventory.
New evidence: Photo of Burnt Cabby
Now you may go back to the previous view, so you'll be able to see the entire cab. Once again, you will have to choose Digital SLR Camera, however this time you will take a picture of the car.
New evidence: Photo of Crime Scene
You should also take a look at the plasters. You will find them near the doors. Listen to what Nick has to say about this.
Your next move is to click on a small spot on the ground. Check the screen if you want to know where it is. Wait for the game to zoom in the view. You will find a small red object here. Pick it up with Tweezers.
New evidence: Red Plastic
You will also have to perform a second action here, so you'll be able to process this footprint in the lab. Click on it and choose Casting Plaster and Frame from the inventory.
New evidence: Footprint from Crime Scene
Once this is done, turn left. There's a large blue container here. You should be able to notice a small gas can here. Click on it. This time you will have to use Latex Gloves.
New evidence: Gas Can from Crime Scene
You should consider clicking on the blue container as well. Open the lid (the right one) and take a peek inside. Listen to what Nick has to say about an insect. Click on the bug. You won't have to use Latex Gloves here. It's going to be collected automatically and it won't appear in your main inventory. I'd strongly recommend collecting all insects, especially since it's not going to be difficult to find them.
Now you should check the area to the right of the cab. There's a hole in the fence here (screen). Click on it and wait for the game to zoom in the view. Once again, you will have to use Latex Gloves. Click on the small blue object.
New evidence: Blue Jean Cloth
Now you will have to inspect this part of the evidence, so don't close the new window just yet. Make sure that you're using four buttons to check this object from various angles. You will have to find a small yellow object (screen). Click on it and choose Tweezers from the inventory.
New evidence: Flake From Blue Jean Cloth
You may go back to the main view of the crime scene. Click on the sewer entrance to receive a point for thoroughness. This is a new addition to the series. You will be rewarded with these points for inspecting areas that could contain valuable objects (but they don't). Obviously I'll show them to you in this game guide.
Now you will have to turn to your right. Make sure that you're looking at the fence. There's a small blue can here. Zoom in the view on it and use Latex Gloves.
New evidence: Turpentine Can from Crime Scene
Once again, you shouldn't close this window right away. There's a fingerprint on the turpentine car. You will have to find it. Next, you must use Fingerprint Brush and Powder. Once the fingerprint is more visible, choose Adhesive Lifting Tape from your tools bar.
New evidence: Fingerprint from Turpentine Can
There are two other thoroughness points here. Click on the right door and on the newspaper. You may leave this area. Head on to the Mobile Lab.