Lost night of 12th/13th August '44, Russelsheim.

Seeking further information on behalf of a crew relative to fill in some gaps on the story of this loss. ME617 was shot down over/just after target and I am trying to establish the cause (flak or fighter)? The sole survivor of the crew of 8 (ABC crew) was the rear gunner Sgt Bert H Cave, who on repatriation was unable to give an account of the night he was shot down. I have full crew list, raid details and details of events after the crash related to burials etc, any further information, particularly on Sgt Cave would be gratefully received.

As this is my first post I would like to confirm that I am an amateur Bomber Command enthusiast (of little or no merit) researching on a non-commercial basis!