CNN - On Tuesday, Mexican authorities announced the arrest of a suspect in relation to the massacre.
But Wednesday, Durazo said investigators have learned the suspect was not involved.
Authorities did not say whether the individual has been released.
While the investigation unfolds, authorities in the US and Mexico have different theories on who might be responsible.
Chihuahua Attorney General César Peniche Espejel said he believes the newly formed Los Jaguares cartel, an offshoot of the infamous Sinaloa drug cartel, may be behind the massacre.
"These very cartels of Sinaloa, after the arrest of Guzman 'El Chapo,' have suffered fragmentations," Peniche Espejel said.
"They have been growing near the border with the United States and are heavily involved in trafficking of immigrants into the United States and drug-trafficking."
But a US official said Tuesday that a rival cartel called La Línea is under scrutiny.