The leaders of Shechem set up an ambush against Abimelech on the hilltops, and they robbed all who passed by them on the road. So this was reported to Abimelech.
Jewish Publication Society of America Version (JPS1917) - Judges 9:25 >And the men of Shechem set liers-in-wait for him on the tops of the mountains, and they robbed all that came along that way by them; and it was told Abimelech.