David Ortiz, the former Boston Red Sox slugger, was not the intended target of a shooting in the Dominican Republic that seriously wounded him last week, the authorities in the country said in a news conference Wednesday. It was a stunning revelation in a case that has captivated many in the baseball-crazed nation and across the world.

The situation laid out by the authorities was far more complex than what had previously been revealed. The shooting, they said, had been ordered by a man associated with a Mexican drug cartel who suspected his cousin had betrayed him and who ordered the cousin killed in an operation that went awry because Ortiz and the target were sitting together and wore similar outfits.

During a 90-minute news conference, Jean Alain Rodríguez, the country’s top prosecutor, explained in detail what was believed to have led to the shooting on June 9, when Ortiz was shot in the back at a popular bar and then had emergency surgery before being transported to Boston.

Rodríguez said both Ortiz and a friend named Sixto David Fernandez, the intended target of the shooting, were wearing dark shirts with yellow trim. The two were sitting at the same table at the Dial Bar and Lounge, a regular hangout for both in Santo Domingo, when a man sneaked up behind Ortiz and shot him in the back.