Go to pay phone, just out of town.
Call the local sheriff, but disguise your voice.
Make sure the sheriff isn't a friend or relative
of this bad person.
Spill your guts to him ALL about the bad person.
(give every detain, and ask him to record it)

Keep the message brief in case they want to
record the call.

Oh, BTW, hide your car up the road and walk back
to the gas station, and don't let the attendant
get a good look at you, and WHATEVER you do,
do NOT talk to him (attendant-or anyone else).

Pick a busy day when he'll be busy pumping gas.

When you're done, walk back to your car,
and run like you stole it.

The sheriff won't be on your tail, because he
just hung up the phone from talking with you.

With any luck, the sheriff will get right on
the case, or give it to his deputy.

(based on watching 1950s TV)