Federal law allows informants, like those employed by the DEA, to engage in “otherwise illegal activity” as part of an investigation. Those activities include “trafficking in what would be considered as large quantities of controlled substances” — 450 kilos of cocaine, for instance, or more than 90,000 kilos of marijuana. Aside from direct involvement in drug deals, law enforcement officials may also allow drugs to flow into communities because they're interested in seizing the cash proceeds from the sale of those drugs. In 2015, the DOJ's Inspector General criticized the DEA for how it tracked and approved the illegal activity of its sources.