A young man, held inside Washington's largest mental hospital, is dead because of a series of preventable mistakes made by state employees. That's the cold reality of a just-released independent federal probe.

KIRO Team 7 Investigators attracted widespread attention to the suicide of Anthony Gordon last year. We uncovered videotape and secret documents that proved Gordon was left unsupervised for too long. He used the time to hang himself from a bed that was supposed to be bolted to the floor.

Now, Investigative Reporter Chris Halsne discovers still more fallout resulting from our work.

The latest indictment of Western State Hospital mistakes in patient care comes from Disability Rights Washington (DRW). That organization has a federal mandate to investigate claims of patient neglect and safety failures inside some tax-funded institutions.

Anthony Gordon spent the last few moments of his life sitting on a bench, rubbing his head -- agitated, and alone.

This never-before-aired Western State Mental Hospital videotape shows at least eleven employees walking around Gordon in the day room. Nobody came over to see how Gordon was doing; no one even looked his way.

After about five minutes of being ignored, he wandered back to his room, tied a sheet to his neck, upended his bed, and hanged himself. He was dead just one day after arriving at Western State for a mental health evaluation.

Now, this just-released federally mandated investigation from DRW, has concluded, "Mr. Gordon's death was a significant and preventable treatment failure.”

Phyllis Gordon has been fighting for more than a year to get answers about how her son died and why he was left alone despite being diagnosed by Western State as having "hallucinations and suicidal thinking."

“I believe they (Disability Rights Washington) really came out with justice and a strong arm for the disabled. They came out saying this stuff happened. Our main objective is that it's got to stop!" she said.

KIRO Team 7 Investigators proved that state employees altered check-up sheets and death reports to make it appear they properly monitored Gordon -- when in fact, they didn't.

Gordon's family has filed a lawsuit, seeking justice, truth and compensation.

Phyllis Gordon recently told Halsne the state has always been evasive about what really happened to Anthony in the moments leading up to his death. That’s why she called KIRO TV and that’s why her family sued.

“They (Western State Hospital) continue to try to cover it up with a new lie and a new lie and a new lie.”

This latest independent investigation states "had Mr. Gordon's bed been secured to the floor of his room, he would have been deprived of the means of hanging himself."

That’s the same conclusion KIRO Team 7 Investigators came up with 6 months ago. We discovered the bed was supposed to be suicide-proof, designed to keep mentally ill patients from harming themselves. Public records we found show those safeguards were not installed by Western State. Basically, the hospital didn’t bolt the bed down to the floor until four days after Gordon killed himself.

Now, taxpayers might pay a hefty price for the failures listed in this report.

The Washington Department of Health and Human Services, which is the state agency that oversees Western State, won’t comment due to pending litigation. The Attorney General’s office has been assigned to defend the mental hospital in ongoing legal proceedings.