Four years ago, U.S. intelligence officers gave their Mexican counterparts the address and home telephone for Jesus Albino Quintero Meraz, a man they thouht was shipping tons of Colombian cocaine from the state of Quintana Roo, on Mexico’s Yucatan peninsula, to the United States.

But nothing happened. In those days, Quintana Roo was a veritable narco-state. Authorities from the governor down through the ranks of the police were bought and paid for by Quintero and his associates in the Juarez-based cartel, U.S. and Mexican officials say, giving them control over much of the multibillion-dollar drug trade on the Gulf of Mexico.

Now, it seems, things have changed in Mexico. Quintero, characterized as an unremarkable thug who nonetheless rose to the top of one of the nation’s biggest drug gangs, was arrested on Sunday along with six associates, including a federal police officer, in the gulf city of Veracruz, the defense secretary and the attorney general announced on Monday.

“He wasn’t famous. He wasn’t glamorous,” said the defense secretary, Gen. Clemente Vega Garcia. “But he was a very important figure in the cocaine trade.”

Vega said that Quintero shipped, on average, 100 pounds of cocaine daily to the United States, often working in coordination with Osiel Cardenas, the head of another major Mexican drug organization, the Gulf Cartel.

The arrest of Quintero, 42, which was carried out by military commandos who are part of a federal drug enforcement unit, is the latest in a series that has transformed the drug wars in Mexico. The demand for drugs in the United States remains high and the overall supply essentially unchanged. But Mexican authorities, working closely with U.S. law enforcement and intelligence officers, have jailed leaders and lieutenants from all four of Mexico’s major drug cartels in the past year, disrupting the gangs’ chains of command.

The chiefs of the Tijuana and Sonora cartels are under arrest, as is the second-in-command of the Gulf Cartel. Quintero is thought to have become the chief operating officer of the Juarez cartel after the arrest last year of Alcides Ramon MagaM-qa, a former federal police officer.

Taken together, the arrests are a remarkable reversal from the 1990s, when the gangs clearly had the upper hand over the authorities.