Dirt crawl spaces, vented and uninsulated are trouble.
The fact that you did not smell a thing in the crawl space when you were down there, might be explained by what we call "stack effect".
It goes like this. As the air warms up inside your house, it tends to rise (like in hot air balloons) and go out through any openings in the upper levels of the house. As it escapes through, the air in the house must be replenished so some cold air is sucked in from the lowest levels of the house. And yes, you guessed it... that means your crawl space.
Studies show that 1/3 of the air you breathe in your house, comes from your basement or crawl space.
So, the fact that you do not smell anything in the crawl space, does not mean the crawl space is not the source of the bad odors, because when you are down there, you are breathing the fresh air coming through the crawlspace vents as the stinky air is being sucked right into your home.
You said it is not a musty smell, so that is good news. You also said you did not see anything rotting or moldy, even better news.
But I'd call a crawl space encapsulation professional to take a look at the problem. Some will inspect it for free.
Oh and I'd also take a look at that wall and that window you mentioned. Is the insulation ok? Is there mold growing in a way you cannot see like behind the drywall? Even though it seems like the mold grows only during the rainy season, moisture is always bad news.
here's more info on crawl spaces: