60's B&W thriller - Escaped convicts terrorize gas station

[Venster]

I saw this film in about 2005. My best guess is that it was made in the late 50's or mid 60's. It was B&W. Much of the film was centered around the events in this one backwoods gas station or auto wrecking yard. There was this one psychopathic (escaped con?) dude and his psychopathic girlfriend and maybe one other partner-in-crime who had the occupants of the gas station tied up or hand cuffed to the cars outside and were threatening them with a gun. Then a while later some police (or sheriff) pulled up in their car, parked at the gas station, and the dude shot them dead. The bodies were left in the cruiser for the rest of the film.
That's about all I remember.

[RCMerchant]

Sounds very similar to the SADIST with Arch Hall-but it was an auto junkyard-and the cops were on mototrcycles...

http://www.youtube.com/watch?v=82MVFDEV_Vs

[Venster]

Thanks RCMerchant. That looks like it! 
Intense and disturbing even by today's jaded standards.

[Venster]

How do I move this to the SOLVED section?

[RCMerchant]

How do I move this to the SOLVED section?

The forum administrater will handle it-...and I'm more than glad to help-all the folks here at BAD MOVIES will help ya out !

[JaseSF]

Actually it could also be The Choppers also starring Arch Hall Jr. although much of your description sounds closer tp The Sadist, some elements also sound like this film...