Erin Benavides -- the woman connected to the Tony Parker/Eva Longoria cheating scandal -- died by self-inflicted gunshot wound ... according to a new report.

Page Six -- citing the Nueces County Medical Examiner’s Office -- reported the news ... stating her cause of death was the gunshot wound and the manner of death was ruled a suicide.

The M.E. noted the full autopsy report won't be released for about a week.

As we reported ... Erin was found dead in her Texas home last month after police performed a welfare check prompted by an alarming text she sent to a friend of her husband.

Erin allegedly had an emotional affair with Tony back in the day ... with Eva reportedly learning about the entanglement after discovering hundreds of texts between them. Erin was married to Tony's San Antonio Spurs teammate Brent Barry at the time.

Both marriages fell apart ... and all parties went their separate ways.

Erin was an assistant district attorney in Texas ... handling high-profile human smuggling cases. She was just 54 years old.

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