Searching for details about Boeing B-17 F Ser. Nr. 42-5885, Mission April 11th 1944

[Rolfeb]

Hi All,
presently searching for more information about the mission dated April 11th 1944.
Unfortunatelly the MACR consists just of the two front pages with info of the palne and short info about the relatives of the crew member.
What I know is the following.
The plane pilototed by 1st Lt. Harry E. Johnson flew a misson at April 11th 1944 together with 917 bombers - mainly to targets in the North East of Germany.

Johnsons plane crashed into the Baltic Sea, no survivers. It seems to me the plane attacked the Heinkel Werke near Warnemünde/Rostock.
On board was the radio operator James H. Learn.
I am looking for the following infos:
Are there any details avialable about James Lean?
What caused the crash? Where they attacked by German fighters of FLAK?
Did the plane belonged to 337th BS that day?
Was the plane ever found?
Is the crew still MIA?

Thank you a lot,
Rolf