August 7, 4:15- Katherine Korzilius

On what could be described as a normal suburban summer afternoon in 1996, turned out to be a parent's worst nightmare. 6-year-old Katherine Korzilius, whose father worked for singer Bon Jovi, was checking the family mailbox and failed to return home. Within a few hours, her family's lives would be forever changed. Katherine's suspicious death even inspired the Bon Jovi song, August 7, 4:15. 

Sources: 

https://unsolvedmysteries.fandom.com/wiki/Katherine_Korzilius

https://www.websleuths.com/forums/threads/tx-katherine-korzilius-6-austin-7-aug-1996.20316/