Men from eight North Jersey towns were among 27 people charged in a state police child porn investigation dubbed "Operation Watchdog," authorities said Tuesday.

The 26 men and one woman used file sharing programs on the internet to download or distribute child porn, the state police said. Among the images and videos were those with a "digital fingerprint" that were tracked as they moved across file sharing networks, authorities said.

Among those charged with possession and distribution of child pornography from North Jersey are:

• Joshua Kane, 31, of Wayne
• Andrew Rodriguez, 27, of Park Ridge
• Jose A. Velasquez, 20, of Clifton
• Joseph Marella, 42, of Passaic
• Scott Hersh, 43, of Mount Arlington
• David Ingoglia, 36, of Byram
• Jeremy Gardner, 18, of Livingston
• Charles E. Jones, 50, of Morristown

“Through aggressive, technology-driven investigations such as Operation Watchdog, we must banish the misguided notion that online viewing and sharing of child pornography is a victimless crime,” Attorney General Jeffrey S. Chiesa said. “The vulnerable children who are tortured and degraded to create these vile materials are re-victimized every time another person views the images."

One of the arrested men, Cesar Salgado-Maya, 23, of Audubon, lived in a residence connected to a day care, police said. Another, Bernard Cahill, 53, of Folsom, took pictures of himself sexually assaulting a juvenile, images that were discovered on his computer, police said.

Cahill was charged with sexual assault and manufacturing child pornography.

“Those who thought they could hide their child porn crimes in the secrecy of their homes have been exposed by the relentless work of law enforcement working together," said Colonel Rick Fuentes, Superintendent of the state police.

More than 100 law enforcement personnel from 21 agencies took part in the three-month investigation, executing search warrants in 26 towns last week.

During one of the raids, police found a 66-year-old Pennsauken man, William Brooks, downloading child porn as authorities stormed in, police said.

Three people, whose names were not released, are still being sought, police said.

“Let the word go out that those who share child pornography over the Internet are also sharing the evidence of their crimes with computer experts from law enforcement, who are patrolling the Internet to stop this tragic victimization of children,” said Stephen J. Taylor, director of the state Division of Criminal Justice.

The photos and images have been turned over to the FBI, police said.

The following individual was arrested on April 11, 2012 and charged with sexual assault, manufacturing child pornography, and distribution and possession of child pornography:

The following individuals were charged with distribution and possession of child pornography

Arrested on March 1:

Arrested on April 9:

Arrested on April 10:

Arrested on April 11:

Arrested on April 12:

Arrested on April 13: