Answer:
Letters and publications written by Nazi leaders before the Second World War.
Explanation:
This answer is correct because this historian is searching for the motives of these perpetrators, letters and publications can tell their thoughts and conversations.
The cultures group of the far north hunted deer
Confederate troops fired on Fort Sumter in South Carolina's Charleston Harbor. Less than 34 hours later, Union forces surrendered. Traditionally, this event has been used to mark the beginning of the Civil War. So the second one.
