On page 399 of the book "Battle of Britain-Then and now" by Winston G Ramsey the entry is as follows
253 Squadron, RAF Kenley
Hurricane L1830
Shot down by enemy fighters on squadron interception patrol.
Believed crashed near Grove Ferry at 8:25am
Squadron Leader H.M. Starr fell dead at Hamill Brickworks near Eastry.
Aircraft a write-off.
I believe that it is in the Geneva Convention that pilots can open fire on an airman on a parachute if that airman will land on home soil and be returned to his unit to continue the fight. I know of Sgt Leslie Pidd who was a Spitfire pilot in the Battle of Britain who was also killed in such circumstances.
I also remember reading about a young Luftwaffe pilot who told his Commanding Officer Adolf Galland that he had done such a thing only to be slapped by Galland and immediately posted from the Luftwaffe squadron to another unit.