ALBANY — Fire engulfed a vacant house on a side street off Albany's Delaware Avenue Saturday morning. The fire at 15 Leonard Place started around 7 a.m., but Albany firefighters were kept at bay to fight the blaze from the outside for hours because of concerns about the structural soundness of the house, Deputy Chief Joseph Toomey said. Officials were still trying to determine late Saturday afternoon if there were any people inside the vacant property, which one neighbor said is a hotspot for squatters and police activity. Both vacant properties were marked with red placards with white X-es indicating they were derelict and possibly structurally unsound.