In this particular case, Reuters seems to be pushing the narrative that there's a Border Crisis.

The dominant players in the illicit opioid trade – the Mexican cartels that manufacture most of the drugs and smuggle them into America– have been the subject of detailed reporting over the years. Now, as the first news organization to buy and test fentanyl’s essential ingredients, Reuters has penetrated the hidden sub-industry that makes the cartel operations possible: the international supply chain of precursor chemicals.

For comparison the Fort Worth Star-Telegram reports:

Nearly three-fourths of those caught attempting to smuggle fentanyl into the U.S. since October 2022 were U.S. citizens, and they brought in more than half of all fentanyl seized by U.S. authorities, the officials said.