It is likely they were attacked by a Ju88G-6 of Luftwaffe Staffel (Squadron) II./NJG 100 which was based in Linz, Austria at that time. Many of these aircraft were fitted with twin 20mm canon mounted at an oblique angle (slanting upward). The Germans called it schräge musik (slanting music) in a reference to jazz. This weapon configuration allowed the fighter to maneuver in from behind and below the bomber attacking it from its weakest defensive point. This configuration and tactic were employed by the German night fighters beginning in November 1944. This would explain the burst striking the bomb bay and the immediate fire on the flight deck which was above and forward of the bomb bay. The fighters did not, as suggested in the reports, mount rockets.