WASHINGTON — The only grand jury witness in a case against a former Olympic canoeist accused of tampering with the Lincoln Memorial Reflecting Pool testified that the area was already damaged and would have required repairs regardless, lawyers said in a court filing Monday.

David “Davey” Hearn was indicted this month and accused of damaging the liner of the long, shallow pool near the Washington Monument. Hearn, who has pleaded not guilty, previously told NBC News that “the condition of the Reflecting Pool was the same after I stepped away from the water as it was before I got there.”

President Donald Trump blamed vandals for the issues with the pool after he announced a plan to coat the bottom with “American flag blue” ahead of America’s 250th birthday. The project faced several setbacks, and the cost grew considerably beyond his original estimates. The coating began coming up and algae flooded the water once the pool was refilled.

The U.S. Attorney’s Office for the District of Columbia did not immediately respond to a request for comment on the filing.

At least three other people face misdemeanor charges in connection with incidents at the Reflecting Pool.

The witness, who is not identified, testified that the property had already been damaged before, authorities say, Hearn stuck his hands in the water, according to Hearn’s team.

He was charged with destruction of property and accused of doing more than $1,000 worth of damage to the pool.

Hearn’s team questioned whether there is enough evidence to show he caused more than $1,000 in damage to the pool, the threshold necessary to charge him with a more serious crime.

The witness’ testimony, according to Hearn’s lawyers, “established that the pool had substantial preexisting damage requiring repair before any alleged conduct by Mr. Hearn.”

The witness said the cost to repair the pool would have been $6,000 to $15,000, based on pre-existing damage in the area.

“Simply put, the government’s witness could not identify any additional cost caused by Mr. Hearn’s alleged conduct. Indeed, the witness did not even say or suggest that the alleged conduct had compromised the liner at all,” they wrote.

The witness testimony also raised questions about whether the grand jury was properly instructed about the core elements of the alleged crime, which “bears directly on whether the felony indictment was lawfully returned,” Hearn’s attorneys wrote.

“The Government’s only witness on that element testified that the property was already deteriorated, that the identified repairs would have been needed even without Mr. Hearn’s alleged conduct, and that he could not quantify any loss caused by that conduct,” they wrote. “Consequently, the grand jury’s indictment of Mr. Hearn is hard to explain. Mr. Hearn needs to learn whether the grand jury was properly instructed that the charge required him to have caused over $1,000 in damages, when the testimony failed to establish that he caused any damage at all. So does this Court.”

The U.S. attorney’s office for Washington handles both federal and local crimes and is headed by former judge and Fox News host Jeanine Pirro.

NBC News pressed Pirro this month about how she would prove Hearn caused more than $1,000 in damage, given that the pool was already damaged in several locations. “With an expert,” Pirro said. “Come to the trial.”