One Dark Night

Six girls have been found murdered in the apartment of famed Russian occultist, Karl Raymarseivich Raymar, and police cannot explain it. When Raymar's body was lifted onto a stretcher, bolts of electricity shot out from his fingers. Not even his estranged daughter Olivia McKenna (Melissa Newman) or her husband Allan (Adam West) knows what happened until they meet Samuel Dockstader (Donald Hotton), a feature writer for "The World of the Occult". Dockstader, once a friend to Raymar, explains that Raymar was a psychic vampire who gained great powers of telekinesis by kidnapping young girls, terrorizing them, and feeding off the bioenergy they produced. Allan does not believe him, but Dockstader shows Olivia a set of photographs to demonstrate how bioenergy works and gives her an audiotape that outlines his findings, which convinces Olivia to believe him.
High school student Julie Wells (Meg Tilly) wants nothing more than to be one of "The Sisters," a club of three snobby high school girlsâCarol (Robin Evans), Leslie (E.G. Daily), and Kitty (Leslie Speights). Unfortunately, Carol is the ex-girlfriend of Julie's new boyfriend Steve (David Mason Daniels), and is jealous. She intends to get back at Steve and Julie by making Julie spend a night alone in a mausoleum, unaware that Raymar's body was just entombed there. That evening, Julie is dropped off by two of the "Sisters", Carol and Kitty, as Leslie had refused to accompany them on the plan. Julie explores the mausoleum and sets up her sleeping bag, unaware of the cracks that appear around Raymar's vault.
Carol and Kitty, hoping to scare Julie, sneak back into the mausoleum in Halloween costumes. They succeed in frightening Julie, who locks herself in the chapel. Suddenly, the walls shake, windows explode, and doors slam shut. Thinking this is the result of Julie being scared, Carol and Kitty decide to leave. When vaults open, coffins slide out, the dead rise and surround them, and Kitty and Carol are buried under a mound of corpses and suffocate.
Meanwhile, Steve has gone over to Julie's house and found her missing. He catches up with Leslie, who reluctantly tells Steve about Julie's initiation, and Steve angrily heads over to the mausoleum. At the same time, Olivia dashes over after learning about her father's powers and the possibility that she might also possess them. Back at the mausoleum, Raymar has broken out of his coffin and is controlling the doors and cadavers with his psychic powers. Steve breaks in and finds a hysterical Julie. They become surrounded by cadavers that advance toward them. Steve tries to fight the cadavers, but they knock him out. Raymar pulls a dazed Julie closer to him just as Olivia arrives. She tries out her powers on her father, but he is stronger. As a last effort, Olivia takes her compact and reflects the bolts from Raymar's eyes back at him, causing Raymar and the cadavers to disintegrate, saving Julie and Steve.
The three, including a traumatized Julie, begin slowly walking out of the mausoleum. The film ends with a shot of Kitty's toothbrush near the mound of corpses, before the bride corpse falls in front, emitting a scream.

Question: Who convinced Olivia McKenna that her father was a psychic vampire?
Answer: Samuel Dockstader