Mexican human rights groups have often questioned the confessions announced by authorities, arguing that they are sometimes extracted by force and have little value.
But Guerrero Gov. Angel Aguirre said that authorities are carrying out the investigation in this case professionally.
"It was never intended to take to jail scapegoats or innocent people in a case as delicate as this one," Aguirre said. "We are working with a high degree of responsibility and with efficiency to erase this black chapter in the history of our port of Acapulco."