MEXICO CITY -  

The Mexican attorney general's office says federal police who ambushed a U.S. Embassy vehicle, wounding two CIA officers, were not investigating a kidnapping in the area, contradicting the official police explanation of the shooting.

An assistant prosecutor says the investigation shows it was a direct attack on the vehicle carried out by 14 federal police officers, all of whom have been detained.

The CIA officers were heading down a dirt road to a military installation south of Mexico City on Aug. 24 with a Mexican navy captain when a carload of gunmen opened fire on their SUV with diplomatic plates and gave chase. More vehicles joined in the pursuit, and the armored SUV was riddled with bullets.

The two CIA officers, who have not been identified, received non-life threatening injuries. The captain was not injured.

Arrest orders have been issued for four commanding officers for allegedly planning the attack.

A senior U.S. official says there's strong circumstantial evidence the officers were working for organized crime in a targeted assassination attempt.