The House Veterans Affairs Committee will subpoena beleaguered VA Secretary Eric Shinseki.
CNN reported Thursday that the subpoena is seeking more information, specifically e-mails, about delays in the VA health system in Phoenix, that possibly led to the deaths of up to 40 patients.
In the e-mails Shinseki and other VA officials may have discussed destruction of what the committee called "an alternate or interim waitlist" for veterans seeking care in Phoenix.
Patient care has also come under fire in Colorado.
Three officials at the Phoenix headquarters were placed on leave a week ago while allegations of corruption are investigated.
Director Sharon Helman, associate Lance Robinson and an unnamed employee were removed temporarily from their positions.
Shinseki has said he will not resign. He answered in a letter Wednesday that VA employees used "transitory or interim notes ... for reference purposes" as they were moving information to the new electronic waitlist system. Regulations of the National Archives and Records Administration require that such notes be destroyed when they are no longer needed for reference, the VA said.
Associated Press contributed to this report.