A grim new photo shows the body of Austin mass shooter Ndiaga Diagne clad in an Iran y-shirt under his “Property of Allah” hoodie –.and investigators also found an Iran flag and photos of the Islamic republic’s leaders in his home, it was revealed Monday.

In the snapshot of the dead suspected terrorist, his corpse is seen sprawled out on a Texas sidewalk outside Buford’s Backyard Beer Garden with a pair of latex-gloved hands peeling back his torn and bloodstained hoodie to reveal the gray tee emblazoned with the letters of “Iran” in the green, white and red of the Islamic Republic’s flag.

Diagne, 53, opened fire at patrons of the popular roadhouse-style night spot early Sunday, killing two and wounding 14 others before police took him down.

Authorities said he was armed with two handguns and an automatic rifle but that he only used two of the weapons before he was killed.

Law-enforcement sources have said officials suspect his rampage may have been in retaliation for the US airstrikes against Iran — with investigators noting they also found a Quran in his SUV, along with an Iranian flag and photos of Islamic republic leaders in his home in Pflugerville, Texas.

Diagne was not previously on the FBI’s radar, according to Alex Doran, acting special agent in charge of the FBI’s San Antonio office.

Doran said at a press conference Monday afternoon that the bureau is still working to determine a motive, poring over “thousands of hours” of video evidence to put the pieces together.

“This is a round-the-clock, 24-hour investigation at this point. Any declarations on motive would be premature,” he said.

“We want to makes ure we have our facts 100% correct or at least track down every possible motive we can because we owe it to the victims and their families to be right.”

Austin Police Chief Lisa Davis said Diagne’s guns were all legally acquired in San Antonio in 2017 and urged the public to be patient as the tragic case unfolds.

“We are making tremendous, significant project in this case, but it will take time,” she said.

Diagne, a former New York City resident, arrived in the US on March 13, 2000, on a tourist visa during the Clinton administration and became a lawful permanent resident when he married a US citizen in June 2006.

He became a naturalized US citizen on April 5, 2013, around the start of former President Barack Obama’s second term, despite several arrests.

A 2017 lawsuit viewed by The Post alleged that Diagne once mowed down a pedestrian in Brooklyn while driving recklessly, causing “permanent personal injuries.”

The resolution of the case was not immediately known.

Cops identified the two fatally wounded victims Thursday as two Texas college students, Ryder Harrington, 19, who attended Texas Tech, and Savitha Shah, 21, a University of Texas student working on a dual-degree in management information systems and economics, according to her LinkedIn page.

Of the 14 victims, three remained in critical condition as of Thursday afternoon.

Wilson said one of the patients was on the verge of being removed from life support, but it was not clear whether that patient was expected to die from their injuries. Cops did not respond to a Post inquiry.