You're welcome, Andrew. Here's a brief account of when and how he was killed. It would appear that he wasn't a POW: ROBERTS, CYRIL EDMUND P/O(FE) 091052//R123750. From Winnipeg, Manitoba. Killed in Action Jun 16/44. #405 City of Vancouver Squadron (Ducimus), Pathfinder Force. Lancaster aircraft #ND 343 missing during a night raid against Lens, France. F/O A.G. Gamsby, P/Os P.S. Greene, J.K. Vivian, W.D. Huff, and WA. Morrill were also killed. Two Canadians, WO Stewart and F/O Bowker were taken Prisoners of War. Pilot Officer Flight Engineer Roberts is buried in the Calais Canadian War Cemetery, Leubringen, Pas De Calais, France.
MORRILL, WARREN ARTHUR P/O(AG) J89461//R191123. From Schreiber, Ontario. Killed in Action Jun 16/44 age 20. #405 City of Vancouver Squadron (Ducimus), Pathfinder Force. Target – Lens, France. Please see Roberts C.E. for casualty list and flight detail. Pilot Officer Air Gunner Morrill is buried in the Calais Canadian War Cemetery, Leubringen, Pas De Calais, France.
https://www.rcafassociation.ca/heritage/history/fallen-aviators/rcaf-casualties-second-world-war/riedy-to-russ/