The lead congressman investigating HealthCare.gov’s dismal performance during its first two months online ratcheted up the executive-congressional conflict on Wednesday, accusing Health and Human Services Secretary Kathleen Sebelius of criminal obstruction of his investigation.The dispute centers around a letter the Centers for Medicare and Medicaid Services sent to a contractor that worked on the online health insurance marketplace, directing it not to turn over correspondence and other documents to congressional investigators and stating CMS would manage any congressional inquiries.That letter amounted to “criminal obstruction” of a congressional investigation,” according to House Oversight and Government Reform Committee Chairman Darrell Issa, R-Calif.“Obstructing a congressional investigation is a crime,” Issa said in a statement. “The federal obstruction laws reflect the fact that Congress’ right of access to information is constitutionally based and critical to the integrity and effectiveness of our oversight and investigative activities.”HHS Spokeswoman Joanne Peters responded that the department is attempting to comply with Issa’s investigation while ensuring it doesn’t reveal any private consumer information or technology secrets.“We have worked to accommodate the committee’s oversight interests in a number of ways, including by allowing the committee to review unredacted copies of the requested documents in person,” she said in a statement. “The committee already has copies of the requested documents that have been redacted to protect sensitive security information.”The department plans to respond directly to Issa later, Peters said.Issa issued a subpoena in October to compel Sebelius to turn over documents related to HealthCare.gov’s troubled launch.