Mark Klein, Whistleblower Who Exposed NSA's Internet Surveillance, Dies at 79

Klein revealed the NSA's use of secret AT&T facilities to conduct mass surveillance on Americans' internet traffic in the early 2000s.

Mark Klein, a former AT&T technician, passed away at 79 from pancreatic cancer in Oakland, California, according to the Electronic Frontier Foundation (EFF).
In 2006, Klein disclosed how the NSA used Room 641A at an AT&T hub in San Francisco to copy and monitor internet traffic through optical splitters.
His revelations provided key evidence in lawsuits against AT&T and the NSA, though these were ultimately dismissed after Congress legalized the surveillance program in 2008.
Klein's whistleblowing preceded Edward Snowden's 2013 disclosures and was credited with inspiring further scrutiny of government surveillance programs.
Despite legal and personal risks, Klein's actions highlighted concerns about privacy, government overreach, and the impact of post-9/11 surveillance laws.