Answer:
Think about the crimes described in the video and about how crimes are investigated now. If the crimes happened today, the investigation will be based on fingerprint with evidence sample. Earlier also they used samples and scents to detect the crime.
Step-by-step explanation:
If the crimes happened today suspects would be fingerprinted and would heck the crime scene for evidence such as blood, hair any type of DNA . Back then there wasn't a way of testing DNA and evidence they just investigated friends , family members and lovers . Back then they used blood hounds to sniff out scents of people who were suspects. Back then they also assaulted suspects until they would confess what they had seen or known .