Winkelhake (courtesy: Clackamas County Sheriff's Office)

The Clackamas County District Attorneys Office on Wednesday, June 11 charged a 40-year-old Hillsboro man with 23 counts related to his sexual and physical abuse of a teenage girl. The Clackamas County Sheriff’s Office stated that there could be additional victims of Seth Michael Winkelhake.

Winkelhake works as an education and volunteer specialist at Clean Water Services in Hillsboro, where he coordinates youth volunteer opportunities, including at Fernhill wetlands in Forest Grove. Clean Water Services did not immediately respond to requests for comment. 

The sheriff’s office shared that Winkelhake also worked with volunteers at Tualatin Hills Nature Center and the Friends of Tualatin National Wildlife Refuge.

According to a press release from the sheriff’s office, the agency received a tip in January about multiple sexual assaults that took place in Clackamas County over the span of four years. The victim reported she began chatting online with someone named Jeff, who claimed to be much younger than he actually was.

“This person convinced the victim to send explicit photos of herself and then used them to blackmail her into maintaining an online relationship,” the sheriff’s office stated. 

A charging document from Clackamas County Circuit Court notes multiple instances of Winkelhake abusing the underage victim between 2018 and 2024.

According to the sheriff’s office, the victim would meet Winkelhake, who would wear a ski mask, at public places in the Oak Grove area. Winkelhake would then blindfold the victim and drive her to parks around Oak Grove where he would physically and sexually abuse her.  

Believing there could be additional victims, detectives with the sheriff’s office encouraged anyone with possible abuse or criminal activity involving Winkelhake to contact them by calling 503-723-4949 or using the online tip form at http://www.clackamas.us/sheriff/tip.

The sheriff’s office described Winkelhake as 6 foot 3 inches and about 200 pounds with red hair and blue eyes. They said he would often go by the names Jeff, Don Jon or Marc and that he used multiple accounts on social media platforms like AntiLand, Facebook and Instagram. He drove both a white 2019 Nissan Frontier pickup truck and a black 2002 Volkswagen Golf.

The 23 current charges against Winkelhake include multiple counts of rape, sodomy, luring a minor, encouraging child sex abuse, strangulation, assault, sexual abuse, coercion and using a child in a display of sexually explicit content.