A top official at the National Park Service says the liner of Washington, D.C.'s Reflecting Pool was cut with a knife or razor earlier this month.In a court filing, the deputy director for operations, Frank Lands, says the cut damaged the foam sealant that was installed as part of the site's $16 million renovation. President Donald Trump has blamed unidentified vandals for peeling paint found in the pool, but officials have not named anyone who may have been involved.One expert told the PBS News