Man Charged with Dozens of Sexual Assault Counts in Oregon and California

Posted on February 7, 2019

FBI and Local Law Enforcement Partners Are Seeking Models Photographed and Potentially Victimized by Robert Arnold Koester

The Federal Bureau of Investigation (FBI), Yamhill County (Oregon) Sheriff’s Office and the Carlsbad (California) Police Department are asking for the public’s assistance in identifying potential victims of a suspected serial sexual predator who took nude photos of models and is alleged to have sexually assaulted many of these models, including individuals younger than 18 years of age. Robert Arnold Koester – also known as Bert Kay, Rhake Winter, and Qitooly – age 52, has potentially been engaging in these criminal acts starting in 1994 and continuing through his initial arrest in Carlsbad, California, on November 13, 2018.

Alleged victims have been identified in multiple cities across the United States. At the time of his arrest, Koester worked as a professional photographer, engaged in the photography of models, primarily on the West Coast of the United States.

At the time of his initial arrest in November 2018 by the Carlsbad Police Department, Koester was living in Southern California. He currently faces 23 felony charges filed by state prosecutors in San Diego County related to that arrest, including child sexual abuse and production of child pornography.

Koester also faces two federal counts of sexual exploitation of a minor in California based on an investigation by the San Diego FBI. Koester remains in custody in San Diego, California.

Koester owns a farm in the rural Carlton area of Yamhill County, Oregon, and a joint investigation by the FBI’s Portland Field Office and the Yamhill County Sheriff’s Office is ongoing.

On January 30, 2019, the Yamhill County Grand Jury charged Koester with 32 felony counts involving four separate victims, one of whom was a minor. The counts included multiple charges for first-degree rape, first-degree sodomy, first-degree unlawful sexual penetration and causing another person to ingest a controlled substance. Koester’s bail on the Yamhill County counts has been set at $2.5 million.

FBI offices in San Diego and Portland as well as FBI Headquarters have been working hand-in-hand with local law enforcement in Carlsbad, California, and Yamhill County, Oregon, and elsewhere to coordinate the law enforcement effort to identify potential victims in this case. As a result, the FBI has created a central electronic system to collect information in an effort to identify all potential victims in order to fully investigate this case.

If you someone you know may have been victimized by Robert Arnold Koester, the FBI requests that you complete this secure, confidential online questionnaire

Information from the public may also be submitted confidentially via email to:

Identified victims may be eligible for certain services and rights under federal and/or state law. More information is available at

An indictment is only an accusation of a crime, and all defendants should be presumed innocent until proven guilty.

Additional Resources:

FBI Help for Victims of Crime Brochure
Caring for Kids: What Parents Need to Know About Sexual Abuse
Adult Survivors of Childhood Sexual Abuse
Suicide Prevention Lifeline
American Psychological Association Resources on Sexual Abuse
Rape, Abuse, & Incest National Network (RAINN)
National Center for Victims of Crime

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