(NewsNation) — One “powerful” cartel is responsible for most of the fentanyl arriving in North Texas, according to court documents obtained by the Dallas Morning News.

Calling it “ultraviolent,” the newspaper reports the U.S. attorney’s office for the Eastern District of Texas identified the Sinaloa cartel as the group to which the majority of illicit fentanyl coming into the area can be traced to.

Sinaloa has some competition, as they have been fighting for control of the fentanyl market with the Jalisco New Generation cartels, federal authorities said.

Because of its low cost and “relative ease” of transportation, fentanyl is used by drug traffickers to increase profit margins, according to a 2020 report by The Drug Enforcement Administration.

A special agent with the Dallas DEA office told the Dallas Morning News that shipments used to be primarily routed through North Texas, where they would then go to other destinations across the United States. It was in the middle of 2020, Eduardo Chávez said, that agents started seeing more fentanyl shipments staying in the Dallas area.

Several indictments beginning in 2019, according to the Dallas Morning News, show that about 100 defendants have been charged in connection to a large fentanyl trafficking conspiracy and money laundering scheme. The news outlet says DEA agents allege a former Plano resident is running “the million-dollar operation” from Mexico.

Fentanyl, a synthetic opioid, can be as much as 50 times stronger than heroin and 100 times stronger than morphine, according to the U.S. Centers for Disease Control and Prevention. It can be illicitly manufactured to lace other pills, and was responsible for more than 100,000 fatal overdoses in 2021.

Fentanyl has been blamed for drug overdoses in a couple Texas high schools, some of them fatal, the DMN said. Last year, at least seven teenagers reportedly overdosed on pills likely laced with fentanyl, including one 15-year-old girl who died on a high school campus.