Jack Weaver of Mn

I am researching my for information on my grandfather. He married my grandmother in Milwaukee Wisconsin in June of 1942. My father was born in August of that year. My father thinks last time my grandfather was seen was my dad was around 3 years of age. At this point in time i have no clue where to even begin to look for him.

My grand father was in the Army/Air force guards. It may be possible that he went to Europe to fight in the war. The records i need for that were burnt in St louis fire. Any information anyone has would be gladly appreicated.