Other than people there are also places to investigate. These are 3D virtual reality worlds. You can look up, down, move around, open objects, pick things up, etc. Like any adventure game it is absolutely vital to pick up everything that you possibly can. If it isn't nailed down, and sometimes even if it is, it is bound to be important somehow.
Items are often inside something or hidden in some way.
You'll have to literally hunt for clues. The down side here is that the interface makes this tedious. As you point at things the cursor will be either a pointer or cross hair. The cross hair means that you can click on the item and get a little menu of what you can do to the object. You might think that isn't important.