Senate Intelligence Committee chairman Dianne Feinstein ripped the Central Intelligence Agency for allegedly illegally spying on the committee’s computers earlier this year. The California Democrat said she is “not taking [the issue] lightly” and has referred it the Department of Justice for possible prosecution.

“I have grave concerns that the CIA’s search may well have violated the separation of powers principles embodied in the United States Constitution, including the speech and debate clause,” she said. “It may have undermined the constitutional framework essential to effective congressional oversight of intelligence activities or any other government function.”

CIA chief John Brennan called Feinstein’s comments “spurious allegations” and was “deeply dismayed” by the accusations.

Feinstein charges that the agency monitored what the committee members did while on CIA computers investigating the agency, in violation of an agreement between the two bodies.