Mexican soldiers stand by a US diplomatic vehicle attacked with gunfire in the Tres Marias-Huitzilac highway in the Morelos state on August 24, 2012. (File photo)
The two CIA operatives injured in a gun attack on a US Embassy vehicle south of the capital Mexico City have returned home despite an inquiry into the shooting case.
Mexican officials on Wednesday acknowledged they had returned to the United States, and asked Attorney General Marisela Morales why the two were allowed to go to the US even though an investigation is underway, The Associated Press reported.
Morales said they were allowed to go "so that they can be treated in the place they think is safest." She added that the two CIA agents could testify later.
On Tuesday, outgoing President Felipe Calderon promised a "thorough investigation with all rigor and severity" would determine whether the shooting was a case of mistaken identity or a purposeful attack.
"Whether the shooting was due to negligence, or complicity, or a lack of training, or a lack of trustworthiness, these events are unacceptable," Calderon said.
The CIA agents were traveling on the Tres Marias-Huitzilac highway, and leading from Mexico City to Cuernavaca -- the capital of the state of Morelos and situated 90 kilometers (55 miles) south of Mexico City -- when their armored vehicle was fired upon by Mexican federal police officers on August 24.
The Mexican Navy said in a Tuesday statement that an American was driving the car, and that during the attack the captain, who was handling logistics and translating for the men, remained in the back seat calling for help on his cellphone.
The CIA operatives were reportedly sent to Mexico to bolster efforts to fight drug traffickers.
Drug violence has reportedly killed more than 50,000 people since Calderon launched an offensive against Mexico's cartels, when he took office in December 2006.