Zilean kills 1 Malzahar + Voidling = Double Kill/Gold?

It's a 13 second video, but it shows Zilean received a double kill from Malzahar's death (and his voidling?) alone. Also to note, Zilean's kill counter increases by one but receives twice the amount of gold from a kill.

Zed assisted in the kill, received twice the amount of gold, and his assist counter increases by two instead.