The Case Of The Deadly Prophecy is a Sherlock Holmes television movie from 1955.
It stars Ronald Howard as Holmes, H. Marion Crawford as Dr. Watson and Archie Duncan as Inspector Lestrade.
A set of strange deaths take place in France and, knowing about his reputation, the lady at the boys’ school sends for Holmes, with Watson joining him as always.
A boy leaves the school at night and writes a name on a church step.
The person then dies.
It seems very supernatural but it’s just the local doctor who has hypnotised the boy.
The doctor tries to get the victims to pay money and if they don’t, he poisons them.
Movie pages here.