DALLAS (CBSDFW.COM/AP) – The Dallas Police Department has thrown out the results of a promotion exam after discovering late last year that a police major who had helped shape the test had a test-prep business on the side.

The Dallas Morning News reports that the city’s civil service board agreed Tuesday with a decision to void the tests taken in November because of the concerns raised by Maj. LaToya Porter’s involvement.

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When contacted by CBS 11 News DPD spokesperson Sgt. Warren Mitchell would not confirm why the exams were invalid or how many participants were affected, but dud say, “… the Civil Service Board deemed the assessment invalid due to possible ethical violations that compromised the integrity of the process.”

About a dozen officers are said to have paid for tutoring through the test-prep company, which investigators said used scenarios that were similar to ones that appeared on the test Porter had helped craft.

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The exam results were to be used for the purpose of determining the order of promotions.

An internal affairs investigation into Porter’s actions remains open.

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(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)