A New Mexico man accused of repeatedly crossing into Mexico and raping at least 13 women in their homes has been formally notified of the charges he faces in a Mexican court.

Gustavo Haro, 32, was arrested Sunday in the sprawling city of Ciudad Juarez, across the Rio Grande from El Paso. According to Mexican authorities, Haro, a U.S. citizen from Sunland Park, N.M., targeted women in middle class neighborhoods since August 2006.

Haro often made his way into the homes of victims by knocking on their doors to ask for jumper cables for his stalled car, or simply by showing them a gun and forcing his way in, police in Juarez said.

"The investigation started about five months ago, and thanks to the help of American authorities we found and arrested this man, the same who was recognized by the majority of the victims," Mario Ruiz Nava, a government spokesman in Mexico, said Tuesday.

Haro remains jailed in Ciudad Juarez, but it wasn't immediately clear whether he had a lawyer there. In Sunland Park, the home at an address listed for a Gustavo Haro was fenced off and inaccessible Tuesday.

El Paso police helped Mexican authorities identify Haro after receiving a partial license plate number and description of his vehicle. Officer Chris Mears said El Paso detectives compiled a list of people whose vehicles and license plate numbers fit the description.

"That information included the person they have subsequently arrested," Mears said.

He said Mexican authorities enlisted help from El Paso police because they presumed the suspect was crossing back and forth over the border.

A man with the same name and date of birth as Haro has been arrested several times by in El Paso, though not since the late 1990s, Mears said. Haro is not listed as a sex offender in any publicly available databases. Mears said he is not believed to have committed any similar crimes in the El Paso area, though police are reviewing open cases for any possible connection.

Mears said Haro is one of a handful of American citizens arrested in Mexico in the last several months in connection with a sex crime.

"We are unique in the country, in that we are the largest U.S. city that abuts that actual international ports of entry," Mears said. "That does create a situation where criminals can take advantage of that situation and cross into Mexico where the forensic abilities aren't the same as on the U.S. side and commit their crimes in hopes of not getting caught."

But with improved cooperation between authorities on both sides of the border, Mears said the chances of being caught have been greatly increased.