Laes first gets mentioned in the Tir Taingire sourcebook... Tir border patrols catch intruders, interrogate 'em, probably mind proce 'em, then strip 'em of their stuff, does them with Laes to forget the previous 24 hours, and dump them over the border to fend for themselves.
Lone Star eventually managed to reverse-engineer it after picking up someone with a fresh enough dose in their system and, from there, it spread around a bit. Eventually the criminal syndicates got wind of it, and it made it out into general circulation, if quite rare, as a rape drug of choice. (It gets mixed with a drink, the victim passes out, and doesn't remember what happened.) ... There are some Humanis-ish gangs of rich punks who started a fad of "Unicorning", where Elf girls woul dbe targeted, abused while recorded, and have their hair lopped off as a trophy. (Based on the old Spur Posse routine, because, you know, you can never go wrong with Humanis thugs as bad guys.)