Question: Why would Luke Dempsey be arrested along with his father? He had no idea what his father was doing, never aided him in any way and only found out the truth after catching him in the act.
Question: How could Eric and Godric be hunting the werewolf pack in 1945 without Pam, who we later learn is made in 1905?
Answer: Pam doesn't have to be with Eric 24/7.
Answer: He helped his father evade capture, impeding the investigation.