California Photographer Took Nude Photos of Dozens of Models—Many Underage—And Allegedly Sexually Assaulted Them at Shoots

robert arnold koester, oregon
Robert Arnold Koester, in a 2016 Oregon DMV photo. Oregon DMV/FBI

Authorities are searching for potential victims of a professional photographer who took nude photos of models—some of whom were below the age of 18—and allegedly sexually assaulted a number of them, the FBI has reported.

52-year-old Robert Arnold Koester—who also goes by the names Bert Kay, Rhake Winter and Qitooly—was arrested last November by officers from the Carlsbad Police Department (CPD) in Southern California where he was living at the time.

A joint investigation by the FBI, the Yamhill County Sheriff's Office in Oregon and the CPD has so far identified multiple alleged victims in cities across the country. According to an FBI statement—which described him as a "suspected sexual predator"—the criminal activity dates back to 1994.

California state prosecutors have filed 23 felony charges against him in San Diego County—where he is currently being detained—including production of child pornography and child sexual abuse.

In addition, Koester is facing two federal counts for sexual exploitation of a minor in California, as well as 32 felony counts in Yamhill County where he owns a farm.

The charges brought against him in Oregon include multiple counts of first-degree rape, first-degree sodomy, first-degree unlawful sexual penetration, and causing another person to ingest a controlled substance.

Investigators are currently trying to identify all of the potential victims and have asked for the public's assistance. As part of the effort, the FBI has set up an electronic system for those who want to provide information.

"If you have information about this ongoing investigation or believe you or someone you know may have been victimized by Robert Arnold Koester, the FBI requests that you complete this secure, confidential online questionnaire," the statement read.

"Information from the public may also be submitted confidentially via email to," the statement continued. "Identified victims may be eligible for certain services and rights under federal and/or state law. More information is available at"