Crüwell was interned at Trent Park, where, on March 22, 1943, he was intentionally placed with another POW, General Wilhelm von Thoma. During their conversation, Thoma disclosed intelligence regarding the V-2 rocket, i.e., surprise that London was not yet in ruins from German rockets being tested at Kummersdorf test grounds he had visited. This led to the British investigating Peenemünde and following confirmation, carried out a bombing raid on the Peenemünde facilities which severely disrupted the program.