Following some high-profile leaks of classified data, the spotlight has been shining on corporations hired to do secret intelligence work for the federal government. The scrutiny came from congressional hearings as well as from a new report on political contributions by private contractors.

Because Edward Snowden, who leaked secret info on the National Security Agency’s surveillance programs, was an employee of a private government contractor, the Senate Armed Services Committee Thursday received a closed briefing that included details about who has access to classified data. Senators heard from NSA deputy director John Inglis; Robert Litt, general counsel for the Office of the Director of National Intelligence; and deputy U.S. attorney general James Cole.

Also Thursday, two Senate panels — the Subcommittee on the Efficiency and Effectiveness of Federal Programs and the Federal Workforce, and the Subcommittee on Financial and Contracting Oversight — held a joint hearing to look into the role of private companies in the U.S. intelligence community.

Called “Safeguarding our Nation’s Secrets: Examining The Security Clearance Process,” the senators heard from members of the Department of Defense and the U.S. Office of Personnel Management.

Absent from the hearings was James Clapper, former Booz Allen Hamilton executive and President Barack Obama’s current director of national intelligence. Clapper testified before Congress in March, denying that his agency conducted any wholesale spying on Americans.

After the leak, Senator Ron Wyden (D-Oregon), who grilled Clapper in March, accused the director of not giving Congress “straight answers.”

As all of this was going on in Washington, the nonpartisan research group Maplight.org released its examination of political campaign contributions from employees and PACs of companies listed as doing classified work, based on the Washington Post’s “Top Secret America” project.

The group’s report shows Lockheed Martin Corp. at the top of the list with over $5 million in contributions, followed by the Boeing Co. with $4.6 million, and Northrop Grumman Corp. with $3.4 million. Booz Allen Hamilton, which hired Snowden, contributed $81,000.

On the receiving end, Sen. John McCain (R-Arizona), the ranking member on the Senate Committee on Armed Services, took in $422,854, more than any other member of Congress. Second is Rep. Charles Albert “Dutch” Ruppersberger (D-Maryland), the ranking member on the Permanent Select Committee on Intelligence, with $225,919.