The unidentified substance that was found splashed on the Vietnam Veterans Memorial earlier this month was the result of vandalism, the U.S. Park Police said today. Sgt. Robert Lachance, a spokesman for the Park Police, said the investigation into the incident is continuing, but the detective on the case had ruled it an act of vandalism. Lachance said he could provide no more details because the probe is still underway. The oily substance was first reported to police the evening of Sept. 7, National Park Service officials have said. Dark blotches were found along a stone curb at the base...