According to the victim's testimony, she, her husband and her young son crossed the border for the day on Oct. 7 and were on their way back into the United States when they were stopped by four municipal police officers outside the Viva Tijuana shopping center, 55 yards (50 meters) from the San Ysidro Port of Entry, said Diana Escalante, a spokeswoman for the Attorney General's Office in Baja California state, where Tijuana is located.

Two of the officers forced the father and son to walk to several nearby ATM machines and then robbed the money they withdrew. Another officer took the wife to a police office located adjacent to San Ysidro's pedestrian crossing and raped her while the fourth officer stood guard outside, according to the criminal complaint the family filed with Escalante's office.

The police later let the family go and the trio crossed the border before contacting U.S. authorities with their story. The husband and wife returned to Tijuana in subsequent weeks and were able to identify the four suspects from pictures of local police officers, said Liza Davis, a spokeswoman for the U.S. Consulate in Tijuana.

The rape victim and her family asked consulate officials not to release their names or their home state, Davis said.

"Extortion is common, but this is a much more serious crime and its not something that happens, or is at least reported to us very often here," Davis said. "This is a positive case in some ways because of the response of Mexican authorities. We are really pleased at how the authorities on this side of the border have responded." Arrested Tuesday night were Officers Hector Manuel Arias, Victor Lopez and Jesus Ortiz. A fourth officer, Benjamin Rodriguez, was detained early Wednesday, Escalante said.

Arias faces rape and abuse of power charges while Lopez and Ortiz have been charged with extortion and abuse of power. Rodriguez, the suspected lookout, is being held on charges he failed to report a crime in progress.