If you do choose to release him, then he will give you a map to his treasure. (The treasure will not appear if you haven't met him or if you choose to slay him instead of freeing him).
If you kill Velehk and quickly loot his corpse before it disappears he gives two scimitars and vestments from Hammerfell.
Another method for obtaining the map and killing him is to release him, then cancel the conversation while he is still talking and quickly attack and kill him before he's finished speaking. A paralysis weapon works well to immobilize him. The map will have been transferred during the chat, and the body is still lootable. (this method does not always work however, as sometimes the treasure will not appear after you have the map if you kill him anyway)
It's not the most direct treasure map you have ever seen. In fact, the map is more than just upside-down and there is no note in it. Most will have trouble looking for it so here is the pinpoint on the world map.
Location of the Treasure: The map is very misleading, get down to the water level and head directly west from College of Winterhold until you come across a rather flat peninsula that appears to have a path going up it. Go off to either side all the way around the peninsula until you can see the large statue of Talos and below that on the ground should be the treasure. The peninsula is just south and a little west of Ysgramor's Tomb.
Another way to find the treasure is by standing by the beached rowboat at Pilgrim's Trench and looking south-east.
Behind the statue of Talos, on the ground by a lantern, is a skill book - The Importance of Where (One-handed).
|Surrounding the Chest|
|Coin purse x 3|
|Amulet of Talos|
|Silver garnet ring|
|Gold emerald ring|
|Gold ingot x6|
|Imperial sword of (Random Enchant)|
|In the chest|
|Copper and sapphire circlet|
|Velehk Sains's locker|
- A Snowy Sabre Cat might spawn nearby, run up and tackle all the booty, making all of it, except the chest, fall through the ground.
- Even though you freed Velehk Sain, and received the treasure map, the treasure may not appear if you wait too long to retrieve it.
- If you die after freeing Velehk Sain and before you retrieve the treasure the Misc. quest to get the treasure will leave.