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Rosemount officer part of team that pursued federal child pornography case

Assistant U.S. Attorney Carol Kayser, Rosemount officer Beth Richtsmeier and Detective Dale Hanson worked together to investigate and prosecute the largest production of child pornography case prosecuted in Minnesota. The perpetrator pleaded guilty and will serve 38 years in prison. (Submitted Photo)

Note: This is the second story highlighting the role of the Rosemount Police Department in uncovering the largest case of distribution and advertising of child pornography ever prosecuted in Minnesota. You can read the first installment in the Dec. 15, 2016 edition of the Independent Town Pages or read it online

In the spring of 2015, officer Beth Richtsmeier of the Rosemount Police Department began following the online trail of a sexual predator who was using Facebook and Twitter to manipulate teenagers into sending nude photos and sexually explicit images.

Richtsmeier started looking into the online harassment after being approached by several current and former students at Rosemount High School who continued to be harassed online years later.

By that August, Richtsmeier felt confident she had identified the man behind the decoy social media accounts as 33-year-old Anton Alexander Martynenko. She had connected with victims across the Twin Cities area and felt she had taken the case as far as she could working alone.

Her supervisors with the Rosemount Police Department and colleagues with the Dakota County Sheriff's Office felt there might be enough to prosecute the case in federal court, but weren't sure what needed to happen next. Richtsmeier sent an email to law enforcement colleagues across the state, inviting them to Rosemount to share information on any similar cases to see if they might be connected to her investigation.

Detective Dale Hanson, an officer with the Minneapolis Police Department who also works as a task force officer with the Federal Bureau of Investigation, came to Richtsmeier's meeting, where she shared information she had gathered so far, "connecting all the dots and putting it all out there," in a detailed PowerPoint presentation.

Within a few days, Richtsmeier and Hanson met with Assistant U.S. Attorney Carol Kayser. Kayser agreed to open a federal case, making Hanson and Richtsmeier the case agents on the investigation. Investigators in Eagan and Chaska, who had both been tracking Martynenko online for several years, also joined the team.

"Then it really got real because it brought (the case) to a whole different level," said Richtsmeier. "It was completely unknown to us what it would mean."

'We've got to end this'

When school reconvened in September, Martynenko ramped up his online activity — soliciting more images from unsuspecting victims and distributing the photos he'd already collected.

"With him recontacting victims, it accelerated things because we knew he was still active, he was still targeting the different victims," said Hanson.

Rosemount's 2015 Homecoming weekend was an especially active time. When Richtsmeier got home from working at the game, her phone had "blown up" with emails from former students being harassed again.

"Anton was active and it was like he was targeting these victims who were back in the area — I got the chills," said Richtsmeier. "It was hard because (the victims) had been away at college and they thought this was behind them, and here it was completely in their faces again."

Hanson, Richtsmeier and Kayser worked throughout the weekend to draft the legal paperwork they would need to begin tracing the online trail of the images.

"Beth's strength was talking to the victims, getting them to give her details that we needed to include in the affidavits," said Kayser. "At the time, we didn't really know how many victims we had, and Mr. Martynenko was getting particularly aggressive distributing the pictures."

Richtsmeier said the victims were also getting more frustrated — some even told Martynenko directly that they were working with the Rosemount Police and the FBI to figure out who he was and what he was doing.

While Richtsmeier said the team understood their frustration, concern was growing that Martynenko might begin to destroy evidence or his harassment would become too much for some of the victims.

"I could see in these messages that boys talked about hurting themselves — we all agreed, as a team, that we've got to end this," Richtsmeier said.

'Be there until we found everything'

On Oct. 2, 2015, investigators executed a federal search warrant at Martynenko's residence in Eagan.

"In our meeting, I said we have to search from ceiling tiles down, look in heat registers, heat vents, look behind everything under the sink, dump out the dirty laundry — we had 12 hours to do a search warrant, we were going to be there until we found everything," Richtsmeier said.

More than 20 officers from metro law enforcement agencies and the FBI spent the day combing the residence for concrete evidence that could be used to prove Martynenko was behind the "sextortion" scheme.

"We went in there with the idea we were going to look in every nook and cranny in that house until we found what we were looking for," Hanson said.

As officers expected, several major pieces of evidence were found hidden above ceiling tiles in his home. Computer forensic analysts on the scene were able to look at several concealed flash drives that contained an elaborate catalog of photos and other images.

Each victim had a folder labeled with their name, age, high school and, in some instances, their penis size. Each folder contained the nude photos from each victim, along with sports photos or clippings, photos and videos of victims while at the gym, or screenshots of online conversations.

In his plea agreement, Martynenko admitted to soliciting nude photos from at least 20 teenagers between 2011 and 2015, but evidence in the meticulously maintained electronic filing system showed even more teenagers and young men were affected by the scheme.

"In addition to having more than 155 minor victims, there were a lot of adult victims — he wasn't just doing this to kids," said Kayser.

'Flabbergasted he would be so brazen'

After realizing the case could quickly balloon out of control, the team settled on a strategy they felt would help get Martynenko off the streets as quickly as possible.

Hanson and Richtsmeier would focus on gathering evidence for 10 to 15 key victims who otherwise had no connection to each other, then base an indictment on their testimony. Reaching out to victims in different states would also ensure the defense couldn't argue the scheme was an elaborate ploy by the victims targeting Martynenko instead, Kayser said.

The two investigators spent several days doing interviews with victims across Minnesota, Wisconsin and Illinois. In some cases, their contact to set up the interview was the first time a victim or their family had been contacted by law enforcement about the sextortion scheme, Richtsmeier said.

"All the victims have very similar stories about what happened to them," said Hanson.

Connecting with victims continued to be one of Richtsmeier's strengths in the case, said Kayser — "She's very good and talking to kids and getting them to talk to her — she's so nonthreatening and so caring."

During an interview in early November, Richtsmeier and Hanson discovered that Martynenko had continued his online harassment even after the October search warrant was executed and he'd hired a lawyer. A 16-year-old victim told them Martynenko, using a decoy account, had continued to contact him that month, threatening to distribute a photo he'd sent when he was 15.

"We were flabbergasted that he would be so brazen to continue doing this," said Hanson.

The investigators got permission to take over the student's Twitter account, and Hanson began communicating with Martynenko directly. As Martynenko's threats became more specific, even setting a deadline for the victim to comply with his demands, the case "shifted into high gear," said Hanson.

"I feel I got maybe a 5 percent feeling of what some of these kids were going through ... because I was operating as the teenage kid," said Hanson. "I was feeling a lot of stress — I didn't want this kid's picture going out because of me."

"We were scrambling because Anton was threatening to send out this kid's pictures unless the kid either came and gave him (oral sex) or unless he sent some new nude images," said Kayser. "We couldn't let any additional photographs get out, so we were forced to arrest him."

'Really wasn't any wiggle room'

After Martynenko's arrest Friday, Nov. 20, 2015, the team spent much of the time between Thanksgiving and Christmas putting together a "reverse proffer" to present to Martynenko and his lawyers where they presented all of the evidence that had been collected in the case.

As Martynenko listened to what the team said they could prove, Kayser said he appeared to be in a "state of denial ... but then he let it all settle in, and I think because of how thorough we had been in investigating the case, there really wasn't any wiggle room for him."

In January 2016, Martynenko pleaded guilty to the production, distribution and advertising of child pornography. In November, he was sentenced to 38 years in prison for the child pornography scheme.

Convincing Martynenko to agree to a plea bargain provided a huge sense of relief, Richtsmeier said. Had Martynenko wanted to bring the case to a trial, the victims would have had to come to speak in court on the record.

"To have all those victims be forced to come in (to testify) is something nobody wanted to do," said Richtsmeier.

Instead, victims who wanted to share their side of the story were able to provide victim impact statements, which were then presented to the judge during Martynenko's sentencing hearing in November.

Kayser said these statements — many collected by Richtsmeier after speaking with the victims and their families — were important to the sentencing because they were the only time the judge was able to hear how devastating Martynenko's harassment had been.

"Many of them mentioned that any time they'd get a notification on social media it would make their heart sink because they knew that meant, probably, their picture was being posted somewhere. You don't really escape that," said Richtsmeier.

"We know from talking to the victims in this case that many of them considered suicide. Many of them started self-medicating with drugs and alcohol because this was such a traumatic event," said Kayser.

'Nobody would have connected the dots'

Being part of a major federal case can be a challenge for smaller police departments like Rosemount, which don't always have the time or resources necessary to pursue that type of charges.

Both Kayser and Hanson said they were impressed with both the dedication Richtsmeier showed to the case, and the support she received from the Rosemount Police Department and, in particular, Chief Mitchell Scott.

"I truly believe that if Chief Scott had not allowed (Beth) to work this case, Anton would still be out there because nobody would have connected the dots," said Kayser. "(Scott) gave her the room to investigate it, and he gave her the room to help us continue to get it done."

For Richtsmeier, the Martynenko case will likely be the case of her career.

"I had never had a case that consumed so much of my time," she said. "It got overwhelming in the beginning... but at the same time, it was just your basic police work. It was time-consuming, just reading and pouring through all the information, trying to connect the dots."