try Manx Museum
enquiries@mnh.gov.im they were putting together (with volunteer help) an index to all Internment records they had (mostly derived from Polic records)
The Church is St Catherines - see http://www.ee.surrey.ac.uk/Contrib/manx/parishes/rn/rushen.htm
for internment camps try
http://www.ee.surrey.ac.uk/Contrib/manx/famhist/genealgy/intern.htm