MEXICO CITY — As Mexican marines closed in on infamous drug lord Rafael Caro Quintero deep in the mountains of his native state of Sinaloa, it was a 6-year-old bloodhound named Max that rousted from the undergrowth the man authorities say is responsible for the murder of a U.S. Drug Enforcement Administration agent more than three decades ago.
While the United States’ motivation to find Caro Quintero never was in doubt — hence the $20 million reward for information leading to his capture — there was less certainty about the commitment of Mexican President Andrés Manuel López Obrador, who had made clear his disinterest in pursuing drug lords.
