That is interesting. I wonder why he didn’t get transferred to the U.S. with the German rocketeers.
Don't know. In my short investigation, I wasn't able to find anything beyond a couple of trial announcements like the one I linked to.
“HAMBURG, Germany (API- Nils Werner Larsson, a Swedish engineer who claimed test wesk to have information on a new Soviet atom-powered rocket, was report- ed Tuesday to have disappeared. Henri Nannen, editor of the magazine Der Stern, who set up a news conference with the engi- neer, said Larsson suddenly left fiarnburg after talking to hvo American intelligence of/idaJs.”
(Typos per source: The (Stroudsberg, PA) Daily Record 10 March 1960, Page 7 http://www.newspapers.com/newspage/29375305/