SAN FRANCISCO (KTVU) - It's one of the fastest growing crimes in America, child pornography.
The FBI says there has been a 2500 percent increase in the number of arrests linked to child porn nationwide in just the past 10 years.
The Bay Area is no exception. In San Francisco, investigators say the victims are getting younger and younger.
KTVU's Tara Moriarty rode along with the two sergeants on assignment to see first-hand how SFPD is cracking down on the epidemic.
"Internet Crimes Against Children" or I-CAC is the name of the unit within SFPD that handles child pornography cases.
At least 100,000 American children are sexually exploited each year, according to the National Center for Missing and Exploited Children or NACMEC.
That's more than the number of people who die from car accidents and illegal drugs combined.
And with the dawn of the world wide web, predators' 'access to children is easier than it's ever been.
"What we do is investigate people that use the internet to exploit children," said Sgt. Chris Servat, who works alongside Sgt. William Heppler in the unit, rooting out those who are producing, possessing, downloading and distributing child pornography.
"The hardest part of my job is um- seeing the victims, dealing with the victims," said Heppler.
The wall inside their office is covered with booking photos of hundreds of predators. It's a reminder of who they've caught and who they have yet to catch.
Shockingly, Heppler says their victims are getting younger and younger these days.
"Most of the cases that we investigate are from age zero to eight," said Heppler.
90 percent of the time, the duo spends behind a computer screen in chat rooms and on various apps, posing as children.
"We just put out a little hook and and i hate to say it but 100 fish come in two seconds," said Servat.
The two admit they've become physically ill poring over the thousands of images of child pornography and the job takes an emotional toll.
"What we are exposed to it's kind of - it's traumatic and it creates PTSD, said Heppler.
"Unfortunately we have to see graphic, graphic material we have to see things involving infants, children it will affect you for the rest of your life," said Servat.
But the two say SFPD provides a mental health program to help them process what they're seeing and deal with it afterwards.
"It's never something you'll ever used to, um I think as an ICAC investigator if you can look at these images and become used to it, that's your time to leave," said Servat.
This past spring, the duo made several arrests involving what they call "persons of trust".... including a swim school instructor, a UCSF psychiatrist, a Boys and Girls club worker and a youth director.
"It's not typically that weird guy sitting in his basement, it's someone who if you looked at you would never think in a million years, this individual has sexual interest in children," said Servat.
A few weeks ago, the team took Moriarty on a rare outing as Servat and Heppler zeroed in on a suspect's home in San Francisco's Pacific Heights neighborhood where they discovered thousands of images of child porn.
"We found a lot more than we anticipated," said Heppler. "The age range of child pornography we found was anywhere from five years old to to 15-16 years old."
The ICAC team showed KTVU photos of past offenders' homes revealing what are called "workstations". Hard drives, computers, elaborate sound systems, child porn movie dvds are stacked high around desks surrounded by foam sound proofing. One picture shows a sleeping bag and bouquet of red carnations lying on the backseat of a car. Investigators tell us the flowers were used to lure young girls.
Servat said often they'll find buckets that suspects will urinate in, so they don't have to leave their "workstation."
"Every once in a while we find one of those places that seems like a movie like you'll see all the creepy dolls.. like, I said, pee jars everywhere," said Servat.
Today's suspect is questioned and then led in handcuffs to the patrol car to be taken downtown for booking.
"He was not happy to be arrested and probably embarrassed .. but [the] city's a little bit safer having someone like that off the street," said Heppler.
The duo says most offenders downplay or minimize their actions, trying to justify themselves by claiming the victims are older than they look.
After a brief interrogation, the suspect is arrested and sent to jail.
It'll be a long night for Heppler and Servat,
"What will cause us to work kind of vigorously through the night is when we find someone that we know has been physically hands on with a child [because] we need to find that kid. We need to find out where they are and make sure they're safe," said Servat.
Since ICAC's formation four years ago, the team has busted 161 suspects.
"They come from every race, every walk of life every socioeconomic background," siad Servat.
The vast majority of predators are men but their backgrounds are varied. They run the gamut from wealthy to poor, old to young, black white, Latino, and middle eastern. Some have sexual abuse in their history, some do not.
The team says it's not just the victims who are getting younger, it's the predators, too. Junior high and high school aged offenders are doing what's called "sexploitation", where they manage to get one partially nude photo of their victim and then threaten the victim with that, getting them to do more serious stuff like videos.
The interrogation process can be frustrating for the team who admits hiding your anger is key.
"We were both taught that it's easier to catch flies with honey than vinegar," said Heppler, who believes the more the suspects trust the team, the more they open up. "The more information we can try to get to help other children who we may not know are victims."
The one question the pair doesn't ask is why.
"I don't know why someone would feel a need to abuse a year old a four year old," said Servat, shaking his head. "I just- part of me doesn't want to know why."
Servat and Heppler offer these tips to parents: know everything your child is doing on the internet, know every password and don't let them use electronic devices in private.
"With the current technology even in the safety of your own home, your child could be- basically sexually abused behind closed doors without your even knowing it," said Servat.
The majority of ICAC's cases are referred from NACMEC which gets tipped off from companies like Facebook, Google and Snapchat, and from parents who stumble across something suspicious in their child's cell phone.
The team's cases cross state and international borders.
"It doesn't matter where you are on this earth, you're going to get brought to justice," said Heppler.
Servat is a brand new father and Heppler has a baby on the way, they wonder if that perspective of being a parent that will make their job even harder.
"But knowing that we're helping children and saving children, and putting these guys away for horrific crimes, it's very gratifying," said Heppler. "And it's kind of what motivates us to keep going."