Which unit sank HMS Diamond and Wryneck on April 27, 1941??

[Ivo de Jong]

During the retreat from Greece the British destroyers HMS Diamond and HMS Wryneck were bombed and sunk by Luftwaffe aircraft off the Greek coast on April 27, 1941.
There was a heavy loss of life, also because both ships had taken up survivors from the Dutch vessel Slamat, which had been sunk earlier.
Can anybody identify the Luftwaffe or Regio Aeronautica unit which was responsible for these sinkings?
Thanks in advance,
Ivo de Jong