My inquiries into the whereabouts of your son have finally yielded fruit, but I fear you will find that fruit to be bitter instead of sweet.
I'm sorry to say that your concerns regarding your son were confirmed. He has been linked with a group of skooma addicts who often beg for spare pieces of gold. My contact provided me with the map in this packet. He informs me that before he could approach your son to pass along your message, he was assaulted by two men who argued with him briefly before dragging him away. The young woman who was with your son, a disheveled Breton, disappeared into the marketplace during the commotion.
Following up with the local guards, my contact was able to discern that the two men were bounty hunters from Vvardenfell who had documentation linking Tashmin to a crime, but inquiries with officials in Vvardenfell have turned up no evidence of either a crime or bounty on your son. My fear: these men work for House Dres and plan to return your son to a life of slavery.
I'm sorry this letter doesn't bear better news.