In Tasimboko , Edson 's troops discovered the supply base for Kawaguchi 's forces , including large stockpiles of food , ammunition and medical supplies , and a shortwave radio . The Marines seized documents , equipment and food supplies , destroyed the rest , and returned to the Lunga perimeter at 17 : 30 . The quantities of supplies and intelligence from the captured documents revealed that at least 3 @,@ 000 Japanese troops were on the island and apparently planning an attack .