A private forensic accountant investigating the killer of her parents for justice after his acquittal gets pursued as she begins to uncover a scheme of corruption

When a meek single-mum accountant investigates her parents's murder, she uncovers corruption in the local government. She must now team up with the framed suspect to stop the destruction of the proofs and expose the real culprits.

A good murder mystery is more than an investigation into who did what and how. It's also an investigation into the why, the motivation. Why were her parents killed?

For the hook, consider narrowing the genre. With her becoming a target, it is already in the realm of Thrillers. What kind of Thriller? Depends on her actions and what she discovers.

Sci-Fi Thriller: While investigating the corrupt acquittal of her parents? killer, a forensic accountant becomes a target after uncovering a mind-altering technology abused by the local government.

Fantasy Thriller: While investigating the corrupt acquittal of her parents? killer, a forensic accountant becomes a target after the guilty in local government discover she is killing them one-by-one, as a changling.

Just write anything that comes to mind, even if it seems cheesy.

and she is also a single mother

In the current story; the forensic accountant decides to take over the case because police refuse to investigate after the suspected killer is acquitted. And as she gets deeper into investigation; she realises that the suspected killer was framed by people involved in government corruption

Depends. A character flaw, or a disability, that would seem to make it impossible for the protagonist to bring the villain to justice might work. Got one in mind?

But staying with your original version for the moment: what is the unique hook in YOUR mind that attracts you to this character -- a forensic accountant -- and this situation, a miscarriage of justice? Of all the stories you could tell, why do you want to tell this one?