So today, I had a fight with someone in wilderniss. He had about 24 hp and he ran out of wilderniss because he was out of food. I tried to attack him another one time but I failed, but suddenly he ran back into wilderniss to attack me with his 24 hitpoints ( he was with dharock ). So I saw him coming so I used vengeance 1 second before he hit me. He hit 40, so he gets a 24 hit back and die. But there didn't appear a message " you killed ... " and I didn't see a drop except just bones. So I thought maybe I didn't kill him or something, I don't know. But he sent me a pm to buy his dharock  back, but I didn't had it. So he thought maybe it is still laying on the ground for me. So the guy I killed ran into wilderniss to check it but he didn't see his items. So I think the items just disappeared or something because I don't have the items and he doesn't have them either.

Maybe someone can explain this?

EDIT : The items appeared after 5 minutes, just like when a player die out of wilderniss