New Jersey authorities have arrested 79 people who they say preyed on children or possessed child pornography after a nine-month, multi-agency sting.

Ten of those arrested are what Attorney General Christopher S. Porrino's office called "hands-on" offenders. They included George Castillo, 36, of Inglewood, California, who authorities said asked undercover police detectives to send a 4-year-old girl and a 9-year-old girl to Los Angeles for sex.

He was arrested at the Los Angeles airport when he showed up to meet the girls, Porrino's office said.

Castillo faces federal charges of transportation of a minor with intent to engage in criminal sexual activity and production of child pornography, as well as state charges that include child trafficking.

Authorities also arrested Joseph Donohew, 26, of Brownsburg, Indiana, who tried to offer an undercover detective money to have sex with a 9-year-old girl. He had bought the girl a nightgown from a Disney movie, authorities said. He was charged in Indiana with attempted child molestation.

The 79 people charged ranged in age from 14 to 75 years old; in addition to the out-of-state arrests, police made arrests in every county in New Jersey.

Those charged with possessing child porn included a Trenton police officer, a swimming coach and a piano teacher.

One person charged with child porn possession was an IT professional from Morris County, who authorities said may have had more than one million files of child pornography. Authorities don't know the full amount yet because they are still investigating all of his computer equipment.

"The men we arrested lurked in the shadows of the internet and social media, looking for opportunities to sexually assault young children or to view such unspeakable assaults by sharing child pornography," Porrino said in a press release.

"Operation Safety Net" was led by the New Jersey Regional Internet Crimes Against Children Task Force. To see all the names of those arrested, click here.

The task force had new tools for the investigation, including a dog named Mega who is trained to sniff out hidden electronics. Child porn can be hidden in files on small devices that resemble Lego bricks or cufflinks, authorities said.

They also used a new mobile cyber forensics laboratory that can check devices for child porn on the site of an investigation, leading to faster arrests, according to the press release.

"We’re even better equipped to uncover the evidence that will keep these offenders behind bars, where they cannot threaten or further exploit vulnerable victims," Porrino said.

In July, Governor Christie signed a new law, which takes effect in February, that further enhances penalties for possession and distribution of child pornography.