No historic opportunity will be lost if the La Plata, Md., Chamber of Commerce declines to publicize the fact the "The Boogey Man" was shot there.

Apart from a house obviously chosen for its resemblance to the house in "The Amityville Horror," the picturesque aspects of "The Boogey Man," an absurd but proficiently grisly horror cheapie now at area theaters, have little connection with the locale.

If director Ulli Lommel has a specialty, it's sadism. Although his continuity is a tattered patchwork of devices borrowed from horror thrillers as venerable as "Dead of Night" and as recent as "Halloween" and "Alien," Lommel can make you recoil and take appalled notice at certain highlights: The heroine being dragged across the floor while bound and gagged and clad only in her undies; a murder victim simultaneously displaying bare breasts and scissors embedded in her neck; the undeniable piece de resistance -- comparable in its way to the severed head in "The Omen" -- of a teen-age couple being skewered through the mouths to achieve a literal kiss of death.The latter sensation calls for a snappier title than "The Boogey Man," which never seems justified anyway. "Kiss Kiss Stab Stab" would be more the ticket.

The terrors supposedly originate in a traumatic childhood episode, depicted in a prologue whose events and background music blatantly echo "Halloween," presumably for quick identification with the same basic target audience -- shrieking teen-age girls and their wisecracking dates. A little boy and girl are shown peeping through a living room window at a man and woman preparing to get down to lewd recreation. The woman spots the children, who are revealed to be her own. She watches approvingly as her lover binds and gags the boy as a punishment for allegedly chronic peeping.

The little girl, merely confined to her room, sneaks out of bed, picks up a large carving knife in the kitchen and cuts her brother loose. We follow two little hands clutching the knife as it goes upstairs and enters the mother's bedroom. A large rectangular wall mirror reflects the ensuing murder, in which the boy repeatedly plunges the blade into the lover's back. Shrieks and fadeout.

Fade-in 20 years later. The little girl has grown into a young wife and mother named Lacey, played by an attractive actress named Suzanna Love, who suggests a cross of Lindsay Wagner with Patty Duke (and happens to be the director's wife). Lacey lives with her husband, son and brother Willie, rendered speechless since the violent night long ago, in a large country house. r

Lacey is disturbed by the news that her disreputable mother desires to reestablish contact. As she watches the meat being carved at supper, she's all too discernibly haunted by memories of another carving knife. Sensing her discomfort, the helpful husband, an indispensable dope, insists that she confront and exorcise lingering bad memories.

He takes Lacey to a shrink-hypnotist played by John Carradine, doing the "guest star" bit that Boris Karloff used to do in Roger Corman potboilers like "The Terror." Under hypnosis, Lacey begins roaring like the demon Pazuzu in "The Exorcist." Chalk up another gratuitous crib from a hit horror movie.

Still not satisfied, the husband drives Lacey back to the original murder house, now occupied by another family but up for sale. The parents are out, but Lacey and spouse are admitted by the kids, a pair of teen-age sisters and their mischievous kid brother, smartly portrayed by David Swim. Entering the murder room, Lacey is soon terrorized by the mirror, which reflects the killing with maddening fidelity. To protect herself from its spell she shatters the glass with a handy chair.

Surpassing even himself, the husband apologizes for Lacey's rashness and then insists on gathering up the pieces and reassembling the mirror at home, the better to purge his beloved of all those frightening phantoms. One gathers that he's a whiz at jigsaw puzzles, because the jagged fragments of the mirror are back together in no time.

The remainder of the movie is wackily ratonalized by this loose connection to the haunted mirror episode from "dead of Night." In Lommel's variaton the littlest shards and slivers of the mirror are endowed with supernatural potency, luring anyone near them into deathtraps or homicidal rages.

The devices never make a sliver of sense, but they allow Lommel and his collaborators (two local filmmakers, cinematographer David Sperling and editor Terrell Tannen, were members of the crew) to assume fitfully effective attack positions. It's difficult to judge whether the payoffs would be enhanced by a more plausible or clever pretext. Probably not. The shocks might even be curiously diluted by a little preliminary sophistication. "The Boogey Man" achieves a certain vicious distinction by putting the occasional spectacular kink in an otherwise motely fabric.