Under Deuteronomy 21, the body of an executed man hung on a tree had to be buried by when?

Answer: That same day

The body must not stay on the tree overnight but be buried that day, "because anyone who is hung on a tree is under God's curse."

“you must not leave the body on the tree overnight, but you must be sure to bury him that day, because anyone who is hung on a tree is under God’s curse. You must not defile the land that the LORD your God is giving you as an inheritance.”— Deuteronomy 21:23 (BSB)