The Trump administration’s case against the former Olympic canoeist accused of damaging the Lincoln Memorial Reflecting Pool is about to fall apart.

Following the draining of the Reflecting Pool last week, David Hearn filed a motion to dismiss the federal indictment against him. In his motion, Hearn argued that the U.S. Attorney’s Office for the District of Columbia failed to preserve the physical evidence against him: the lining of the pool that he is accused of damaging.

Hearn’s attorneys said in their motion that they had made a written request for federal prosecutors to preserve the evidence, but the pool has repeatedly been drained more than once since his arrest, and large sections of the liner are missing.