Mournful Crow said:
I'm doing research into Nazi Germany and WW2, and I came across some sources that included this event. From what I've read, it's hard to determine what credible sources I can find on the subject. Is there anyone who can help me find a credible source that isn't biased any which way?
There's no such thing as an entirely unbiased source! There was significant misinformation, espionage, and propaganda throughout that region at that time, so it's very difficult to come to a firm assessment with regard to what happened.
As a rule of thumb, regard any contemporary source which is either German or Polish as being suspect, and any secondary source which is either Nazi or postwar communist will likely have extreme interpretive bias.
I'd probably stick to post-1990 assessments and investigations, but I'm afraid I don't have anything specific.