I've let Arvel the Swift ran away, can I still find him?

I've let Arvel the Swift ran away after freeing him.

I didn't know he had the golden claw in his possesion.

So, now I can't complete that quest anymore... Where can I find him?

Solution 1:

Keep moving along the path. You'll find he's met an unexpected fate at the hands of the denizens deeper within the barrow, allowing you to retrieve the claw again.

Solution 2:

For me, the game glitched.

I chased Arvel, followed him into the room with the draugr, watched him die, killed off the draugr, and his body was missing. I checked all around, only to find his body back in the spider web I cut him down from.