The U.S. Justice Department announced it is targeting doctors and drug dealers in its latest crackdown on opioids, The New York Times reports.

Attorney General Jeff Sessions announced a case that accuses two doctors in Ohio of illegally prescribing opioids. One doctor was also accused of Medicare fraud and accepting kickbacks from a drug manufacturer. In addition, an Ohio couple was charged with selling fentanyl and other drugs on the dark web. In a news release, Sessions said at the time of their arrest, the couple “were the most prolific dark net fentanyl vendor in the United States and the fourth most prolific on Earth.”

The Justice Department also indicted leaders of the Zheng drug trafficking organization. These traffickers allegedly manufactured—in China—more than 250 types of synthetic drugs, including synthetic opioids and deadly fentanyl analogues that they distributed in the United States and around the world, Sessions said.