Labor trafficking, which involves forcing or coercing an individual to work, is deemed an "invisible" crime. Frequently, labor trafficking does not involve online "footprints" which makes it difficult for investigators to detect it and ultimately prosecute individuals who are involved. This crime disproportionately impacts vulnerable members of society, such as new migrants to a country. Additionally, law enforcement is often unaware of labor trafficking laws, so these cases are confused with other crimes.
See "Labor Trafficking Is A Crime You Probably Don't Notice", Julie Dahlstrom, WBUR, October 29, 2019