In a sign that a criminal probe into Steward Health Care has picked up steam, a prominent member of the company's board of directors, former U.S. House speaker John Boehner, appeared at the federal courthouse in Boston Thursday where a grand jury is investigating allegations of fraud, bribery, and corruption within the national health care chain. Boehner ignored several questions from the Globe Spotlight Team at the John Joseph Moakley Federal Courthouse. Boehner, who recently received a federal subpoena, was inside the courthouse for two hours. As a member of Steward's board, Boehner was privy to key financial details about the company as its financial situation cratered and patients' lives were imperiled by staff and medical equipment shortages.
