Eusebius said Achor had to be south of Jericho because he did not believe Jesus could be hooked up with where Achan brought sin upon Israel, but Joshua 7 shows us that the death of Achan sanctified Israel through justified stoning and burning.
And Joshua said, Why hast thou troubled us? the LORD shall trouble thee this day. And all Israel stoned him with stones, and burned them with fire, after they had stoned them with stones.
And they raised over him a great heap of stones unto this day. So the LORD turned from the fierceness of his anger. Wherefore the name of that place was called, The valley of Achor, unto this day.