"At the moment everything points to the fact that there will be people to charge," said attorney general Maries Morales. "We're now carefully analyzing the conduct of each officer to ascertain what exactly they can be charged with."
The CIA has declined to comment on the incident. Mexican authorities have detained 14 people in connection with the case.
Cooperation between US and Mexican forces has increased since Mexican President Felipe Calderon launched a military offensive against drug cartels in late 2006.
A greater number of US security officials have been discretely working in Mexico to aid in Calderon efforts as the battle between warring drug gangs and the government escalated. More than 60,000 people have died in the violence since 2007.