After searching around on Google, perhaps it is The Return, a sci-fi film from 1980?
Plot summary from Wikipedia:
While stopping at a gas station late one night in a small New Mexico
town called Little Creek, a young girl gets out of the vehicle while
her father goes inside. Exploring the empty main street of the town
she meets a local boy, and both are soon mesmerized by a column of
light from above. After a minute or two the light disappears and the
young girl runs back to her father's car and they soon leave.
Twenty-five years later, the deputy marshal of the town (Vincent) is
investigating a strange case of cattle mutilations with few leads to
follow so far. His efforts are soon hampered by a scientist from
California (Shepard). As the two conflict over the mutilations and
their possible causes, they find themselves attracted to one another
in an almost-familiar way, as if they share some unknown bond. As
events unfold, they discover that they were the children shown at the
beginning of the film and that the night depicted then changed their
The boy stayed and became a deputy marshal while the girl went
back to California, but she always felt a strange urge to return.
Along with the blossoming romance between the two, the mutilation case
comes to a head when the culprit appears to be a crazy old prospector
hermit living alone on the outskirts of town (Schiavelli). The plot
thickens, however, when the hermit claims that not only were the
children visited by aliens that fateful night twenty five years ago -
but so was he.
To make matters worse, the mutilations have a purpose -
he has been carving out parts of the cattle and teleporting them into
space using a device secreted away in a cave behind his cabin. While
confronting the man near the device, an otherwise fatal blow from the
alien "knife" fails to kill or even harm her. After being saved by the
deputy, it becomes apparent that it was all an experiment by the
aliens who then leave with whatever results they garnered from the
Edit: there's a clip on YouTube: http://www.youtube.com/watch?v=wKDx0_Eym3I