Do you know what this roach killer was?

about 25 years ago i remember a chalk that i paid .10 for at a store boy howdy , this chalk was look just like a piece of chalk that you would write with, you could take it home and just put a mark on your cabnits or any where and you wouldnt beleave the drifference , it would kill 1000 of roaches and other bugs in a matter of a few hours. I have been looking for this stuff and i cannot find it anywhere on the little box it came in was only written in japanese or chinese .and i know it wasnt boric acid. If anyone knows what im talking about please let me know.thank you.