PHILADELPHIA -- The FBI arrested two men who did computer work for a powerful state senator Wednesday on charges that they permanently deleted e-mails to thwart a federal investigation. Leonard P. Luchko and Mark Eister performed electronic "wipes" of computers at Sen. Vincent J. Fumo's Senate offices, his home at the New Jersey shore and at a nonprofit with deep ties to Fumo, authorities allege. "This was a deliberate, systematic and ultimately successful effort to interfere with a federal investigation," U.S. Attorney Patrick Meehan said. "We have to assume that valuable information is lost forever." The document does not name...