Whether any of the following is true or not could take fifty pages of writing. Therefore here's the assumed history. Jacob Waltz shot and killed his nephew because he was going to publicly record the mine. They were on their way back to Phoenix via Fort McDowell and camped at Agua Escondido. The argument broke out the next morning. Waltz buried his nephew in soft dirt under a ledge.
Agua Escondido is spanish for hidden water. Appropriately enough this is a hike to Hidden Water Spring. The hike is simple. You can start anywhere around Cottonwood Camp and hike down the creek. Personally I take FR401 to the point where it really turns into 4x4 as mentioned in the directions below. If you don't have a truck good in sand you will need to add on 0.5-1.0 miles to the hike. Okay, head south down Cottonwood Creek. The creek is a wide sandy base that's extremely popular with ATVs. Hike about 2 miles to the confluence with Cane Spring Canyon. If you weren't looking for the confluence you might miss it as it does slip in at an extreme angle.
Enter the tributary and soon the pace slows down. The canyon gets dense with trees and prickly bushes. It's barely a quarter mile into the spring. Return as you came. Interesting to note, this tributary to Cottonwood Creek spans way up towards the Four Peaks and has several tributaries of its own. It must flow high at times. I imagine it would be a real site from above with it's twisty turns at the end.
Check out the Official Route and Triplogs.