Here is what I have about this possible loss:
A Bv 138 C-1 (unknown WNr or code) from 1.(F)/SAGr 130 was shot down by a Soviet aircraft and crashed off Gamvik area, Norway. Its five (unknown) crew were killed. Its was claimed shot down by the lieutenant Aminiev, pilot of a Boston of the Soviet North Fleet.
Source:
http://www.rafandluftwaffe.info/lists/luftwaffe1.htm
Article on Soviet Bostons by Viktor Koulikov, Aéro-Journal n° 25 (French magazine, June-July 2002)