At 2232 EDT, the aircraft was climbing to 15,000 feet when the pilot reported a low oil pressure light. ATC advised Jimmy Stewart Field is about eleven thirty and 15 miles. After the pilot asked, 'Is that a tower field?', ATC advised he did not know. Westmoreland County is at two o'clock and about 15 miles, turn right 180 degrees, descend and maintain 4,000 feet. At 2233 EDT, ATC said that they believe Westmoreland County tower is closed down. The pilot said that he was thinking of where he should go and ATC advised Pittsburgh's 35 miles away if you can make that. At 2234:35 EDT, the aircraft was returning to Pittsburgh when the pilot reported zero oil pressure and an oil light. At 2237:27 EDT, the pilot reported an emergency. Flight was cleared to Allegheny County Airport and advised Monroeville Airport 230 heading and 5 miles. The aircraft crashed at 2247 EDT. The investigation showed a loose flange nut on left turbo charger feed line finger tight. Test produced a steady leak. At site oil covered bottom of fuselage and empennage.