Diamond Skulls

Diamond Skulls (also called Dark Obsession) is a 1989 British thriller drama movie. This movie was directed by Nick Broomfield. Broomfield also co-wrote the movie. "Diamond Skulls" includes the last performance by Ian Carmichael.
Plot.
Lord Hugo Brockton is a young Englishman. He is the heir to a vast fortune. He is married to a woman named Virginia, or "Ginny" in short. Ginny seems devoted and loyal to Hugo. They have a young son. But Hugo is haunted by jealousy, as he imagines Ginny in the arms of a colleague. He begins spying on her. He gets angry over her supposed infidelity.
One night, after a social gathering with members of his British Army group, Hugo and his friends go out for a drive. He accidentally runs over a woman, who dies at the scene. All except one of his friends urge Hugo to drive on. In his drunk state of mind, Hugo had imagined himself running over Ginny.
Over the next few days, a psychological war takes place. Peter, who is Hugo's business associate, wants to use the cover-up to get power over the estate. A man named Jamie is dating Hugo's sister. He wants to go to police and report the incident. But Hugo's family closes ranks as Ginny and the rest side with Hugo. He fears his arrest and being sent to prison will hurt the family's reputation. When the police investigation closes in on Hugo, the power struggle leads to deadly consequences. 
At the end, Peter and Hugo murder Jamie and arrange to make it look like a suicide. They wish to make it look like it had been Jamie driving the car who killed the woman. They throw Jamie's dead body off a seaside cliff. The police believe the story and close the case. 
Rating.
"Diamond Skulls" is rated NC-17 by the Motion Picture Association of America.
Reception.
The movie was given two thumbs up by Roger Ebert and Gene Siskel. Other critics' reviews were mixed. The Los Angeles Times gave a positive review to the movie.