It's an interesting theory, but according to the news story most of the audit/ investigation was done in 2016. As an accounting tech, she would have helped the auditor with that investigation back in 2016. If they had a problem with her work, something would have happened in 2016-2017. Sounds like she was still employed, so it seems unlikely she was under pressure for anything. At this point, her work on the audit was probably finished.
The problems seem to be with private contractors who were doing work for the city sewer system. At this stage of the investigation, they're making those folks show receipts, come up with an explanation or repay some money.
So, no, I don't see where she was involved in any wrongdoing. That would have come out a long time ago, at the earlier stages of the audit. JMO