I'm Martin's son, Ken. I found him listed erroneously as "Maria Knapp" on the website for the 401st Bomb Group (401bg.org). It was a listing that included his crew and his pilot, as well as his position in the plane (ball turret gunner). There was also a photo on that page showing my dad as a member of that crew.

The website author suggested that corrections be sent to this website because you have more resources dedicated to updating your information. I'm hoping that you can correct his name, and that it automatically ends up updating that website, too.

Drawn from the records of the National Museum of the Mighty Eighth Air Force, Savannah, Georgia / http://www.401bg.org/Main/History/Members/Details.aspx?ID=2010