In May 2023, the Humboldt County Sheriff’s Office began investigating Matthias Alexander Wilberger of Eureka for suspected possession of child pornography. On June 30, 2023, Wilberger was arrested under PC 311.11(a) after admitting to possessing illegal material.
A forensic search of Wilberger’s cellphone uncovered a large number of additional images and videos classified as child pornography. The content found led authorities to amend his charges to include PC 311.11(c)(1), possession of more than 600 images, and PC 311.11(c)(2), involving sexual sadism and masochism.
Wilberger pled guilty to both charges on December 13, 2023. On January 26, 2024, he received a sentence of five years and eight months in state prison; however, the judge suspended the execution of this sentence and placed him on probation instead. Conditions included registration as a sex offender, completion of a treatment program, and serving one year in the Humboldt County Correctional Facility.
After serving part of his sentence—168 days—Wilberger was released from custody on July 12, 2024.
On May 22, 2025, during an unannounced compliance check at Wilberger’s residence by a sheriff’s detective—a routine part of public safety measures ensuring sex offenders follow legal requirements—the detective found material on his cellphone that violated probation terms. Wilberger was subsequently arrested for violating probation.
Wilberger admitted to these violations in Humboldt County Superior Court on June 18, 2025. On September 16, Superior Court Judge Neel imposed the original state prison sentence.
The Humboldt County Sheriff’s Office highlighted the role compliance checks play in maintaining public safety by verifying accurate records in the registry and addressing non-compliance among registrants. These checks are intended to confirm residency information is up-to-date and restrictions are followed.
“This case demonstrates the critical importance and effectiveness of these compliance checks conducted by law enforcement agencies throughout Humboldt County.”
The agency also acknowledged efforts by the Humboldt County District Attorney’s Office in prosecuting such cases.
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