It is very possible to find the substance called opium along side heroin.
The term hard drugs are often used to refer to those illicit drugs that people take for different purposes and are often trafficked illegally around the world. Some of the them however are used medically as pain relievers.
If Hiroshi is testing for heroin, then he is also likely to find the drug opium as an additive.
Learn more about opium: https://brainly.com/question/4953359