I was in sg 2 and killed somebody, then I automatically died and it said that the person I just killed killed me with coal ore.
That's because when he died, he was at spawn, and his hand was holding the coal ore. Possible he killed you just as you killed him.
Pretty much what Navyseals said. It's not a bug and just means you killed each other at the same time. Sometimes, the items are kind of funny xD.
