Immediately after the deadly May 2018 shooting at Santa Fe High School, one man who said he had witnessed the bloodshed featured prominently in news reports.

Calling himself David Briscoe, the man appeared in Time, CNN and The Wall Street Journal as a substitute teacher whose selfless heroism saved the lives of many pupils.

Over and over again, he told how he ordered his students to “get down”, and then protected them until police arrived.

In April 2019, nearly a year after the shooting, Mr Briscoe contacted The Texas Tribune, hoping to offer more of his wisdom and experiences from the tragedy.

In a half-hour interview with the newspaper, Mr Briscoe recounted his terrifying encounter with mortality. Chillingly, he spoke of how, when the initial shots rang out – “it was very, very loud” – he ordered his classroom of remedial English students to muffle their screams with their hands.

He barricaded the doors. Turned off the lights.

“Just knowing that there’s blood on the walls where you walk at … I don’t think I could go back,” he said.

He and his students were rescued by law enforcement officers. But Mr Briscoe said he quit teaching altogether and moved to Florida, three months after he had taken the job at Santa Fe High.

Dimitrios Pagourtzis. Photo: Getty

It was a spell-binding account of a traumatic crime committed by 17-year-old student Dimitrios Pagourtzis, who has been charged with 10 counts of murder and 13 counts of attempted murder.

But after investigating some of his claims, the Tribune decided it would not publish Mr Briscoe’s account of the shooting – because it appears it was all an elaborate hoax.

It was unmasked when Tribune journalist Alex Samuels decided to do some investigating of Mr Briscoe’s claims.

6/ When he responded via Twitter he said he never talked to me and that someone stole his identity.

FWIW: The @Statesman told me that David Briscoe was tweeting about the shooting around May 18, 2018 — which prompted them to contact him. pic.twitter.com/CDl9995Dnw

— Alexandra Samuels (@AlexSamuelsx5) July 1, 2019

She discovered that nobody named David Briscoe was employed by the local school district.

Police told her they had “no record” of a person by that name working at the school and that there were no English classes – remedial or otherwise – on the side of the school were Mr Briscoe claimed to be working when the shooting began.

“We are extremely disappointed that an individual that has never been a part of our school community would represent themselves as a survivor of the mass violence tragedy that our community endured,” Santa Fe independent school district superintendent Leigh Wall said.

“This situation illustrates how easily misinformation can be created and circulated, especially when the amount of detailed information available is limited due to the still ongoing investigation.”

“We are extremely disappointed that an individual that has never been a part of our school community would represent themselves as a survivor of the mass violence tragedy that our community endured,” said Santa Fe ISD Superintendent Leigh Wall. https://t.co/h0nribUWaL

— Zahira Torres (@zahiratorres) July 1, 2019

Samuels also pored through public records that showed no David Briscoe lived in Texas at the time.

The Twitter account – @daviddbriscoe – that was used to contact the Tribune in April has since disappeared and all four publications that quoted Mr Briscoe have amended their stories.

Public records show Mr Briscoe had a home address in Florida at the time of the shooting; there’s no record of him ever living in Texas.

The tale has echoes in similar episodes relating to previous traumas.

Tania Head claimed she was inside World Trade Centre’s south tower when a plane was deliberately flown into it on September 11, 2001.

According to The New York Times, Ms Head told of “crawling through the chaos and carnage on the 78th floor that morning”. She said she encountered a man whose dying wish was to have his inscribed wedding band returned to his widow.

She told her story to college students and had it posted online as part of the official World Trade Centre Survivors’ Network.

But a spokeswoman for the company Ms Head claimed to work for said she it had never employed her.

In the meantime, the man behind the David Briscoe account blocked inquisitive reporters from his Twitter account and denied he ever portrayed himself as a shooting witness. He initially claimed a former employee of a social media company he had started had stolen his identity.

He refused to reveal that person’s identity.

Not long after that, he stopped responding to requests for comment.

-with agencies