Yahoo sent a letter to Director of National Intelligence James Clapper on Wednesday, asking that his office clarify alleged government-mandated email scanning to the public, CIO.com reported.
The former employees say Yahoo built a custom software program to perform the searches, but Yahoo has denied the existence of such a program.
The Yahoo email scanning story raised eyebrows because although U.S. phone and internet companies have sent data in bulk to federal agencies before, this could be the first time a company was asked to turn over such a broad amount of data or to write a program to collect it.
The Yahoo letter to Clapper said news stories about email scanning have "provoked broad speculation" about Yahoo and U.S. government activities and asked Clapper’s office to “clarify this matter of public interest.”
Microsoft Corp. is also battling the U.S. government on this issue. Microsoft is currently involved a lawsuit that challenges the government's claims it can block companies from telling their customers when their data has been examined by federal agents.
Several companies and lobbying groups — including the U.S. Chamber of Commerce, Delta Air Lines, Google, Fox News, Apple Inc. and Amazon.com — filed legal briefs in support of Microsoft in September.
The Justice Department has maintained that the 1986 Electronic Communications Privacy Act (ECPA) allows it to obtain electronic communications without a warrant in cases where the data could endanger an individual or an investigation. Microsoft asserts that the government is violating the Fourth Amendment, which establishes the right for people and businesses to know if the government searches or seizes their property.