Recently stumbled across this Spanish case from the early 90s. Basically an abduction of 3 teenage girls followed by brutal rape and murder. I found it fascinating how one of the 2 perpetrators is known but has never been caught/seen since 1993 and remains on Interpol's most wanted list to this day. A couple of theories are around as to what happened to him but we may never know.
https://en.wikipedia.org/wiki/The_Alcasser_Girls
https://en.wikipedia.org/wiki/The_Alcasser_Girls