Five young men travel to a basketball game and disappear.  Months later the remains of 4 men are found under mysterious circumstances.  The remains of the fifth, Gary Mathias, has never been found. 

https://www.mentalfloss.com/article/532063/bizarre-hell-disappearance-yuba-county-five

http://charleyproject.org/case/gary-dale-mathias

https://www.sacbee.com/news/local/crime/article226544615.html