PHILADELPHIA — Seven people are facing felony charges after at least two federal buildings in Philadelphia were vandalized on New Year’s Eve and the discovery of what police said were Molotov cocktails and other suspicious devices. Officers reported spotting about 50 people, all in black, around 8:30 p.m. Thursday at the historic U.S. Customs House, police said. And a man was seen throwing a brick through the windows of a federal building and courthouse shortly before 9 p.m., police said. Damage to the federal building was estimated at $3,000. Anti-police and anti-prison graffiti were scrawled on walls, a sheriff’s van was defaced and several windows were broken, police said.