Burger Chef murders
1978 CE.
Shown on the map at 39.796°, -86.262°.
On the night of Friday, November 17, 1978, four young employees at a Burger Chef restaurant in Speedway, Indiana, went missing in what was initially thought to be a petty theft of cash from the restaurant's safe. By Saturday morning it became a clear case of robbery-kidnapping, and by Sunday, when their bodies were discovered, a case of murder. While investigators believe they have identified some or all of the perpetrators, without physical evidence they have not been able to prosecute those who remain alive.
Text from the Wikipedia article Burger Chef murders, licensed CC BY-SA 4.0.