PASCAGOULA, Mississippi -- Jackson County Sheriff's investigators arrested a 19-year-old woman and charged her with possession of child pornography, authorities said today.

Courtney Lynn Necaise, of the 1600 block of Seville court in St. Martin, was arrested late Thursday night at her home, Sheriff Mike Byrd said.

The three-week investigation was conducted with the department's Internet Crimes Against Children computer system.

The system is used to catch anyone downloading and saving child porn on computers. The method uses advanced technologies to track down suspected child predators, and it usually takes several weeks of investigation and surveillance to make an arrest.

Necaise is the first woman to be caught with the system, and Byrd said she is the first Jackson County woman to be charged on a child porn offense.

There were 23 men arrested on child porn charges last year, covering every socioeconomic group. There were only three arrests on child porn charges in Jackson County in 2009, and only two total arrests in 2008 and 2007. All of those arrested were men.

"It's was really kind of bizarre," Byrd said. "They got to the house thinking it was a man, because it's been nothing but men up until now, and it was a woman. A woman involved in kiddie porn is just kind of strange."

Byrd said Necaise had downloaded and saved images of children in sexual situations as young a 6 years old.

"This was not teenagers she was looking at," Byrd said. "This was small children, anywhere from 6 to 11 years old."

Byrd said Necaise offered no excuse or reasoning for downloading child porn. He said the case remained under investigation.

Necaise was released from the Jackson County Adult Detention Center on Friday night on $25,000 bail.

She faces up to 40 years in prison if convicted of possession of child porn.