I watched this because it was supposedly adapted from Lovecraft's Lurking Fear, and indeed it is.
The main house in it, I thought to myself, resembled the house Fletch inherited in Fletch Lives (1989). In fact, it is!: the Ashland-Belle Helene Plantation, Geismer, Louisiana, USA. I think it's unlikely they were both shooting there the same year. Dark Heritage seems like it could be several years older than its copyright date.
A reporter is sent to do a story on some campers that have been killed (we only see that two are attacked, but evidently more were). The newspaper's owner has the manager offer the reporter to stay in a nearby house about which he is also curious. The manager thinks it's a really bad idea, but the reporter agrees and has two other guys willing to join him.
Something happens during the night, and the two other guys are killed; the reporter flees. No evidence is found afterward, but a videotape they'd made shows up in the reporter's car mysteriously. He researches the house and the area in a library, where he meets two parapsychologists who are also interested in the house.
The new team of three goes back, and they discover strange holes in the ground around the house...
I don't think there will be any big surprises for anyone who has read Lovecraft's story, or the two other movie adaptations of it (Lurking Fear, and Bleeders AKA Hemoglobin). However, it is a good amateur effort.
