The administration of United States President Donald Trump has announced felony charges against a former Olympic athlete for allegedly harming the Lincoln Memorial Reflecting Pool in Washington, DC.

At a news conference on Thursday, US Attorney Jeanine Pirro accused professional canoeist David Hearn, 67, of deliberately vandalising the pool.

“Today, a grand jury has returned a felony indictment against a defendant, David Hearn, for felony destruction of property, for which he faces 10 years in prison,” Pirro, a Trump appointee, said.

She proceeded to call the destruction of national monuments “one of the most offensive images” she has ever seen.

“This unchecked vandalism and civil disorder turns into criminal behaviour, and that’s why we’re here today,” Pirro said. “They are an affront to the dignity of our shared history.”

But in media interviews, Hearn has denied any vandalism, saying that, like many Americans, he was simply curious about the Reflecting Pool when he visited on June 19.

The Reflecting Pool had been the subject of a renovation effort Trump began in April, as part of a wider initiative to reshape Washington, DC, through controversial construction and maintenance projects.

Trump awarded a no-bid contract to a firm to seal and resurface the granite pool in a colour he dubbed “American flag blue”. But observers noted that, as soon as the pool reopened in early June, it suffered an algae bloom, and blue paint began to peel from its bottom.

Faced with criticism about the $13.1m renovation contract, Trump countered that vandals had sabotaged the Reflecting Pool.

At least seven people, including Hearn, have been arrested on allegations they may have harmed the pool’s blue-painted bottom.

Hearn has maintained his innocence. He says he was cycling by the Reflecting Pool when he stopped to look at the peeling paint, and he reached in the water to feel it. He denies removing any part of the pool.

Pirro, however, described a different scene. She said National Park Service employees observed Hearn “forcefully and violently pulling up and removing the bottom liner with both hands”, damaging roughly 2 square feet — or around 0.18 square meters — of pool sealant.

“A parks employee actually told Hearn to stop his behaviour and stop what he was doing. Hearn reacted by shouting at that parks employee,” Pirro alleged.

Reporters confronted Pirro with questions about whether charging Hearn with a felony was disproportionately punitive, since similar cases have been considered misdemeanour offences.

One journalist asked Pirro if her decision to seek a felony indictment was influenced by Trump, who wrote on Truth Social that a 10-year prison sentence should “be fully enforced” for any attempted damage to the Reflecting Pool.

“I didn’t charge anything harshly. I charge according to the evidence,” Pirro replied. She argued that Hearn caused damage exceeding $1,000, thereby necessitating a felony charge.

She also dismissed comparisons with the millions of dollars in damage caused by Trump supporters during the attack on the US Capitol on January 6, 2021. Nearly all of those defendants were pardoned on the first day of Trump’s second term.

“Are you really talking about January 6th? I’m not,” Pirro told one reporter. A hearing in Hearn’s case is scheduled for July 9.

On Thursday, preparations for the July 4 fireworks show began at the Reflecting Pool, with large nets spread across the entire structure.

According to a police officer on the site, the nets are intended to catch the debris that could fall into the pool during the show. The site remains fenced off to visitors.

Still, many have come to look at the pool and see the controversial renovations firsthand.

Brian Williams, a 31-year-old from Roscoe, Georgia, praised Trump for his efforts to beautify the city. He said that algae was normal for a pool full of still water in the heat of summertime.

“I don’t think people have any business vandalising anything,” Williams added. “If you have something that you dislike about the president, don’t take it out on the people’s pool.”

But others were more sceptical of Trump’s claims. Jon Delgado, a 40-year-old Navy veteran from Collierville, Tennessee, expressed frustration at seeing the Reflecting Pool in its current state.

“I came here with my wife and my family to show them the beauty of America, the spirit of what we fought for,” he said. “To see it trashed like this, it just makes me angry.”

Delgado called Trump’s accusations about vandalism at the site “really crazy”.

“We have just got to ask ourselves: Is this where we’re at, in the state of America, that we’re believing something like this? You can look for yourself: This thing has pond scum all in it, and it stinks. There’s no vandalism,” he said.