SARA CARTER: Who’s spying on who? FBI’s use of NSA foreign surveillance program needs to be investigated, say whistleblowers.

A controversial NSA surveillance program used to monitor foreigners was also being used by the FBI as ‘backdoor’ to gain warrantless access to American communications, according to numerous former U.S. intelligence and law enforcement officials with knowledge of the program.

The whistleblowers, who recently disclosed the program’s process to Congressional oversight committees, say concern over the warrantless surveillance mounted when it was disclosed earlier this year that Obama officials had accessed and unmasked communications of members of President Trump’s 2016 campaign, allegedly without clear justification.

The process, known as ‘reverse targeting,’ occurs when intelligence and law enforcement officials use a foreign person as a legal pretense for their intended target, an American citizen, the officials stated. The program, as it exists, failed to prevent terror attacks and in many cases made incorrect connections between a foreign target and an innocent American, they stated.

The whistleblowers said the program established after the September 11, 2001, attacks has not been successful in preventing terror threats, but instead infringes on privacy rights and could easily be abused for political purposes. Those concerns were also voiced to then FBI Director James Comey in 2014, and alternative options for the program were discussed, a source with knowledge said. And now, those intelligence officials want lawmakers to conduct extensive investigations into the program.

“The program can be misused by anyone with access to it,” said a former Intelligence official, with knowledge of the program. “There needs to be an extensive investigation of all the Americans connected to President Trump and the campaign who were unmasked in connection with the 2016 election.”

FBI officials declined to comment for this story.

There’s been a lot of no-commenting lately. But this fits in with a lot of stuff we’ve been hearing about the use of intelligence and law enforcement agencies for political espionage.