Murder by Music (1969)

"A terrifying climax to a frightening situation..."

Katharine Milford commits suicide by jumping out the window. Her brother, Richard refuses to believe the police story about suicide, and when it is discovered that more people had contact with Katharine died in the same way he starts a private investigation, which leads the man into Londons 'dirtiest hippie clubs. It seems that music is the common factor in all suicide - or was it murder?