where is the npc i have to steal double distilled skooma?

[Spurmwhale]

this for skyrim. i'm trying to do this quest for last hour searching for the skooma i'm supposed to steal and its driving me nuts. tried google with no luck. help pls.

[conscript]

Use the megathread for threads like this. Also use UESP to find such things. It says he is in the New Gnisis Cornerclub in Windhelm (haven't done it personally, still in my quest log).
http://uesp.net/wiki/Skyrim:Some_Light_Theft