Mexican Defense Minister Ricardo Trevilla said Monday that intelligence leading to the military operation came from a romantic partner of the crime boss, Reuters reported.
The cartel reacted to its leader's death with violence across Mexico, placing roadblocks and setting vehicles on fire throughout Sunday.
President Claudia Sheinbaum urged calm Monday, and authorities said all the more than 250 cartel roadblocks across 20 states had been cleared.
The U.S. State Department said its personnel in cities across Mexico would shelter in place Monday, urging U.S. citizens in many parts of Mexico to do the same.
Oseguera Cervantes was the leader of one of the largest narco-terrorist cartels in the country.
The criminal network was notorious for trafficking fentanyl, methamphetamine and cocaine to the United States, and staging brazen attacks against government officials who challenged it.
Fox News’ Anders Hagstrom and The Associated Press contributed to this report.