A multi-agency investigation into child pornography possession resulted in the arrests of four Chittenden County men, including one from Milton, the Vermont Attorney General’s Office said at a press conference last Thursday.

Brendan Sullivan, 22, of Milton was among those implicated in Operation Peer Review, a three-day undercover investigation into peer-to-peer networks and file-sharing software.

Others arrested include 28-year-old Lukas Vopenka of South Burlington and 30-year-old Suin Sun of Winooski, both charged in state superior court. Shane Martensen, 45, of Burlington, faces federal charges for possessing child porn, court documents show.

Police say Sullivan used uTorrent to search for and download 32 files of child pornography in January. Sullivan performed the search at his respite provider’s home in Jericho but lives full-time with a caregiver in Milton, an affidavit says.

Sullivan told police his caregivers caught him with child porn in 2014, but he wasn’t charged criminally, and that he has mood disorder and pedophilia disorder among other mental health issues, the affidavit says.

Sullivan pleaded not guilty at an April 18 arraignment to felony charges of promoting a sexual recording and possession of child porn, court documents say.

Investigators said there’s no evidence the men knew one another, or that the pornography they viewed was produced in Vermont.

Vermont AG T.J. Donovan lauded the work of the Vermont Internet Crimes Against Children Task Force, a group of 16 agencies that investigate and prosecute crimes of child abuse and exploitation.

In the last three years, VT-ICAC has seen a 157 percent increase in tips, conducted 664 investigations and arrested 87 people, Donovan said.

“This is scary stuff that’s happening in our state,” he said, later adding, “This is incredibly, incredibly difficult work.”

The presser was held at the Sen. Leahy Center for Digital Investigations at Champlain College, both associate members of VT-ICAC. Donovan was surrounded by investigators, including VT-ICAC Commander Matthew Raymond, who spoke to the increasing threat to children as technology advances.

One tool VT-ICAC uses is K9 Mojo, an electronic-sniffing yellow Labrador retriever, who can detect devices the size of a person’s fingernail. Mojo has drastically reduced the man-hours required to search an entire house, Raymond said.

The commander said the taskforce receives tips from the National Center for Missing and Exploited Children, Google, Facebook and the general public.

Authorities still have to issue subpoenas to these providers, Donovan said, and some have denied turning over evidence stored on servers overseas. He pointed to the U.S. Congress’ recent passage of the CLOUD Act, which compels American tech companies to provide evidence regardless of where it’s stored.

“This is happening so fast, you get a fundamental question of is technology outpacing the law? And can we keep pace with technology? It’s proving to be difficult when we are in a global environment,” he said.

And the authorities are reviewing a massive amount of data. Since October 2015, VT-ICAC has reviewed 238,000 terabytes of information from electronic devices. Champlain College students from the LCDI help extract it for trial, center director Jonathan Rajewski said.

Despite the resources available in Vermont, Raymond said law enforcement can’t “arrest our way out of this problem.” He said VT-ICAC urges prevention by advocating for parents to monitor children’s internet use.

“When you give a child a digital device, you’re giving them access to talk to anybody in the world,” he said.

Electronic-detecting dog, K9 Mojo, is pictured at a press conference held by the Internet Crimes Against Children taskforce at the Leahy Center for Digital Investigation on Thursday, May 31. (Courtney Lamdin | Milton Independent)

The investigative work alone takes a toll. Therapist Sonny Provetto, a former Vermont State Police peer support officer, works with VT-ICAC to help officers process the gruesome material they investigate.

The effects of repeated exposure to child pornography are classified under post-traumatic stress disorder, Provetto said, noting an ICAC officer’s work has a similar effect as an officer-involved shooting.

“They have no protection,” he said. “It’s the click of a mouse and then, boom, you can see the most egregious thing you’ve ever seen.”

Indeed, Donovan said he couldn’t bear to look at the images these officers see every day. Provetto helps investigators process the unthinkable crimes by encouraging self-care, he said.

“When you think a stray adult man walking in a parking lot is a predator, then you know the work is affecting you,” Provetto said. “That’s what these folks fight every day.”

Sullivan is next due in court June 22. He was released on conditions to not contact minors or use the internet, among others.