Stalag IIIa and Stalag Luft IV Question

[Paul E.]

I'm trying to resolve some confusion I have about Stalag Luft IV and Stalag IIIa (Luft IIIa?). I have a friend who was a ball turret gunner, therefore an NCO, on a B17 late in the war. He was shot down and taken prisoner by Serbians. I've heard him mention that he was in Stalag IIIa and being forced to march for a month or two to another camp before being liberated at the end of the war.

I looked up his name in the US POW registry and it says that he was in"Stalag Luft IV Gross-Tychow (formerly Heydekrug) Pomerania, Prussia (moved to Wobbelin Bei Ludwigslust) (Usedom Bei Savenmunde) 54-16." I doubt that he was marched from IIIa to IV because I understand that Stalag Luft IV was the starting point for the "Death March" of 1945. Could Stalag IIIa have been the final camp from which he was liberated?

Can anyone shed some light on this?

Thanks, Paul