In 1990, members of the British heavy metal band Judas Priest appeared in a Nevada courtroom accused of responsibility for the deaths of two young men from the state 5 years before. 20yo James Vance and 18yo Ray Belknap had committed suicide and the parents accused the band of placing subliminal messages in their song 'Better By You, Better Than Me'. The prosecutors claimed that the band had hidden subliminal messages like “try suicide,” “do it” and “let’s be dead” in the song, and that this had influenced the two who had spent six hours drinking, smoking marijuana and listening to the metal band’s Stained Class album, after which each man took a shotgun and shot himself. James survived for a few years, though disfigured and heavily reliant on pain medication, and placed the blame on the band. He wrote: “I believe that alcohol and heavy metal music, such as Judas Priest, led us or even ‘mesmerized’ us into believing that the answer to ‘life was death,'” After James' death his parents were clearly distraught and were eventually persuaded to prosecute the band. The prosecution was largely financed and managed by various fundamentalist Christian groups who were opposed to the influence they claimed that satanic youth culture, like heavy metal music, was having on their kids.
The attorney for the families, Ken McKenna said 'a musical engineer played the album backward and discovered the phrases “Sing my evil spirit” and “Fuck the Lord.” Once you see and hear the subliminals, they’re unmistakable.' At the trial the song - and others by the band - were played backwards and forwards to reveal these and similar subliminal messages. In defence, the band's singer, Rob Halford, played Sinatra songs and other entirely innocent music backwards to the judge and revealed messages like "Eat a banana". Eventually the case was dismissed.
The whole idea of backmasking (inserting a phrase backwards) was a thing musicians have done since mixing recordings. The Beatles did it in their album Revolver, but the accusation here was that was playing a record forwards contained secret, subliminal messages that were heard unconsciously but could be revealed when played backwards. The 'messages' however were just Apophenia, or audio pareidolia - the brain ascribing meaning to sounds that seem like voices. Once a meaning has been applied, or given to the listener by someone else, it is impossible not to hear it. As Halford said at the trial, 'If we'd wanted to put subliminal messages in our songs, we'd have said "buy more records"'.