The Santa Rosa de Lima cartel began its reign in the state of Guanajuato, pilfering oil from pipelines that crisscross that area of central Mexico and siphoning off amounts estimated at one point to be valued at nearly $2 million a day.
As the head of a small start-up cartel, which analysts say was largely run as a family crime group, Mr. Yépez showed uncharacteristic pluck, challenging both the government and much larger and more diversified criminal groups.
In emotional videos, Mr. Yépez has often lashed out at his enemies and even threatened the president himself if federal troops were not withdrawn from his native state, where they had been sent to fight fuel theft.
But the government of Mr. López Obrador, which has placed paramount importance on the oil economy, kept targeting the oil racket. Already this year, the authorities had arrested Mr. Yépez’s mother and sister, prompting additional emotional videos.
The revenue from the oil theft, meanwhile, was too lucrative for other criminal organizations to resist — specifically the much larger and more prominent New Generation cartel of Jalisco. The fight between the two groups made Guanajuato the country’s deadliest state last year, with more than 3,000 killings. This year, it is on track to exceed that figure.
“We are talking about a state with 12 homicides a day, and 360 murders in the last month alone,” said Eduardo Guerrero, a security analyst in Mexico City. “That’s 15 percent of the nation’s homicides.”
The New Generation cartel also tried to assassinate the head of security in Mexico City in a brazen daytime fusillade in June.