B&W Boy Returns from Vietnam War a Vampire

by Jason
(Canada)

Does anyone remember a black & white 60's vampire movie about a young man that returns from the Vietnam war and moves back in with his father?

He has become a vampire, and his dad thinks he's been doing drugs because of the needle marks in his arms (he shoots up blood).

In the end, a group of teenagers attack the house and/or town.

It wasn't a bad movie, and the actor that played the father was a known actor - not big, but known. Thanks.