Law enforcement officials across the Twin Cities are expressing alarm with the rising number of complex child pornography cases they are facing, including one thought to be among the state’s largest examples of child porn production.

That case, which began as a report to a Rosemount High resource officer of students’ nude images being posted on social media, led to federal charges in November against an Eagan man for a “sextortion” plot where victims, said to be in the hundreds, are still being found.

Anton Martynenko, 32, is in federal custody and accused of posing as a young woman online to solicit nude photos and videos from high school boys in Minnesota, Wisconsin and Illinois. He then allegedly distributed the images online — offering to share victims’ photos hundreds of times apiece.

“It’s out of control,” officer Dale Hanson, a Minneapolis police digital media examiner, said of such cases. “There’s more out there than you’re capable of dealing with at this point.”

The Hennepin County Sheriff’s Office is seeking help from private forensic analysts. Meanwhile, Anoka County is directing specialized forensic examiners to target child porn reports that were on pace for a 45 percent increase in 2015.

Statewide, the Bureau of Criminal Apprehension has seen cyber tips from the National Center for Missing and Exploited Children climb to as many as 160 per month, up from 60 to 90 a month in 2014, said spokeswoman Jill Oliveira.

The increasing number of cases investigated and charged — the U.S. attorney’s office said it has doubled 2014’s cases — signals to some the growing ease of access to high-speed Internet and file-sharing services among criminals. Others are calling it a product of better collaboration among agencies.

Hanson, who is also on an FBI task force, helps agencies around the state identify suspected child pornography cases. Many cases first appear as a yellow pushpin on a Google Earth map of Minnesota, generated by a software program that Hanson uses to spot potential suspects.

When Dakota County Sheriff Tim Leslie and Capt. Jim Rogers pitched an electronic crimes task force they displayed a map Hanson produced that was pocked with dots showing suspected child porn cases that weren’t being investigated at that time.

“That was a strong sell,” Rogers said. “It was one of the turning points.”

The task force is a pilot project that includes the sheriff’s office and either personnel or funding from eight participating Dakota County departments. Its funding expires at the end of 2017. Citing an increasing workload, Leslie said he has been looking at a larger workspace for the team in case city and county officials keep it afloat.

Meredith Peik, a digital evidence technician with the unit, said it had taken on roughly 50 child porn cases this year, which can take at least 40 hours per case. Every device needs to be analyzed to try to identify victims — some may be missing children — and seizures can involve scores of devices.

“It’s not uncommon to find terabits of data with every victim’s identities,” Burnsville Police Detective Tim Vaughn said.

Task force investigators and Hanson were among those who began looking into Martynenko this summer, even creating a fake Facebook account to which he allegedly offered to share porn. The scale of evidence found at his home — mostly on a thumb drive hidden in the ceiling — was massive: hundreds of digital folders with images of boys mostly younger than 18, sorted by name, age, hometown and school.

“After we looked at the scope, we knew this was bigger than district court,” said Rogers, who supervises Dakota County’s task force.

Martynenko’s attorney, Marsh Halberg, said both sides are still working through the evidence.

“At this point it’s just too early to tell where it’s going to go,” Halberg said.

Cat and mouse game

The Minneapolis office in which Hanson works is warmed by the many columns of computer towers that line the room, their cooling fans emitting a steady whir. Many of the cases that agencies tackle begin as referrals from Hanson — those little yellow pushpins — or from efforts like the Internet Crimes Against Children Task Force and the National Center for Missing and Exploited Children.

Hanson said any rise in child porn cases is at least partly a product of the ability to more cheaply store troves of data. Other investigators point to faster Internet speeds and the ability to share images with so many people.

Assistant U.S. Attorney Katharine Buzicky added that agencies like the Department of Homeland Security and the FBI have been bringing prosecutors more cases with repeat offenders.

And Brian Hill, a former Anoka County sheriff’s detective who now works at Computer Forensic Services in Minnetonka, said the perceived anonymity offered by the dark corners of the Web is also a factor. Like others, he said, these criminals communicate within their own networks.

“You’re just a Google search away from figuring out the next step,” Hill said.