Since 2019, the number of Americans killed by fentanyl has jumped 94 percent. Today on "Post Reports," we go inside Operation Sour Cream — and inside the pipeline bringing the deadly drug from Mexican labs to U.S. streets.Read more:In 2019, Drug Enforcement Administration agent Brady Wilson noticed big loads of synthetic drugs, like fentanyl, popping up around St. George, Utah. St. George is not exactly known as a hot spot for drugs; it’s a sleepy city of retirees, out-of-town hikers and Mormon churches. But Wilson had a gut feeling; he suspected a Mexican cartel had set up shop in town. That would be the beginnings of Operation Sour Cream, a federal investigation into the origins of synthetic drugs in the St. George area.  Synthetic drugs have arrived in small cities and rural areas across the United States abruptly, with immediate, devastating impact. In Utah, fentanyl overdose deaths have increased 300 percent over a three-year period, killing 170 people in 2021, according to the state health department. Mexican criminal groups have become experts in producing fentanyl and meth across the border. Now, Wilson knew, they were honing their role in retail distribution in the United States, where synthetics had reshaped the geography of drug demand.Today on “Post Reports,” Mexico City bureau chief Kevin Sieff reports on Wilson’s investigation into how fentanyl ended up in St. George, Utah, and what this increased presence of synthetic drugs means for the opioid crisis in the United States. This story is part of Cartel RX, an investigative series from The Post looking at the deadly fentanyl pipeline from Mexican labs to U.S. streets.This kind of work is only possible because of the support of listeners like you, who subscribe to The Washington Post. If you’re not a subscriber yet, now is a great time to start. You can also gift a Washington Post subscription to someone in your life who could use this kind of valuable reporting. Check out our latest subscription deal at postreports.com/offer.