Hell Night (1981) on Netflix

The film opens with a girl starts to scream hysterically looking upwards to the camera. During a massive college party, Peter Bennett, the president of the Alpha Sigma Rho fraternity, decides to make four pledges: Marti, Jeff, Seth, and Denise told to stay at the historic Garth Manor until dawn on hell night as part of their initiation. Peter and a group of others, along with his friends Scott and May, bring everyone together and tells them about the sordid history of the estate as they walk while he leads them. Peter explains in a long monologue that 12 years prior, the owner and great-grandson of the founder and gold prospector, Raymond Garth, strangled his wife Lillian to death and then proceeded to murder three of his children (Morris, Suzanne, and Margaret) due to their severe deformities. After the carnage, Raymond hanged himself. However, the police never found the body of the youngest Garth child, 14-year-old Andrew. Legend has it, Andrew witnessed the murder of his entire family and may still be living within Garth Manor.