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Date:  Dec. 11, 2014


Construction Foreman Arraigned on Fraud Charges

SAN BERNARDINO, Calif.  – Osbaldo Serna, 34, of La Habra, was arraigned Wednesday on allegations that he and the owners of a now-defunct Ontario construction company defrauded their workers’ compensation insurance company out of more than $260,000 and stole from their workers over $160,000 in prevailing wages.

On October 23 and 24, investigators from the San Bernardino County District Attorney’s Office and officers from the La Habra Police Department arrested Serna and Miguel Contreras, 35, and Dora Contreras, 34, both of Chino.

Miguel and Dora Contreras, who are married, were the owners of National Drywall. National Drywall contracted with the Colton Unified School District to assist in the building of the new Joe Baca Middle School.

“This was a public works project and therefore prevailing wages were required to be paid by National Drywall to its workers,” said Senior Investigator Phil Jonas, who was assigned to the case.

It is alleged that notwithstanding the requirement to pay prevailing wages, Miguel Contreras and his cousin Serna—who was the foreman—devised schemes to avoid paying the prevailing wage. In addition, during the course of the investigation, it was also discovered that Dora Contreras may have committed workers’ compensation premium fraud resulting in approximately $260,000 in underpaid premiums.

The arrests were a culmination of a two year investigation based on a referral from the Carpenters/Contractors Cooperation Committee (C/CCC), which is a non-profit organization established pursuant to the federal Labor Management Cooperation Act of 1978.

According to Senior Investigator Jonas, the C/CCC monitors construction projects and works with enforcement agencies to ensure that fair bidding, high standards and quality workmanship can prevail.

When contractors violate the law, workers and their families suffer from stolen wages, added Jonas. Law-abiding contractors cannot compete for projects. Taxpayers also lose out from unpaid revenue that could fund needed public services, such as education, infrastructure or public safety.

Dora Contreras is scheduled to be arraigned Dec. 23 and Miguel Contreras is scheduled to be arraigned Dec. 29, both at the San Bernardino Justice Center. Deputy District Attorney Michael Chiriatti will prosecute this case.

Please Post the Following Announcement:

The San Bernardino County District Attorney's Office, Workers’ Compensation Fraud Prosecution Unit, responds to various reports of Insurance Fraud as a result of suspected fraud claims provided by an insurance company. If you suspect that someone you know is or has been involved in Workers’ Compensation Insurance Fraud, report your suspicions to the San Bernardino County District Attorney's, Workers’ Compensation Fraud Prosecution Unit, by calling the WCF We-Tip line at 909-891-3344 or via email at You can also visit us on the web at

Additional Links

For more information about the District Attorney’s Workers’ Compensation Fraud Unit visit


Phil Jonas
Senior Investigator
(909) 382-7604


San Bernardino County District Attorney’s Office
303 West 3rd Street, 6th Floor
San Bernardino, CA 92415



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It is the mission of the San Bernardino County District Attorney's Office to represent the interests of the people in the criminal justice system, as mandated by California State law. The San Bernardino County District Attorney's Office serves the residents of San Bernardino County by: seeking the truth, protecting the innocent; holding the guilty accountable; preserving the dignity of victims and their families; and, ensuring that justice is done while always maintaining the highest ethical standards.

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