"To date, the Committee’s investigation has been characterized by wild and unsubstantiated political accusations that turn out to be completely inaccurate after further investigation," they wrote in a letter addressed to Issa on Thursday.
"In fact, the Washington Post Fact Checker has awarded you 12 Pinocchios over the past 12 months for inaccurate claims you have made during this investigation. We believe it is time to end these seemingly endless and unsubstantiated political attacks and direct the Committee’s efforts towards concrete and lasting reforms."
The letter comes after a contentious hearing on the IRS "targeting" scandal earlier this month where Issa abruptly cut off Ranking Member Elijah Cummings (D-MD)'s microphone. Democrats expressed outrage and demanded Issa step down, but House Speaker John Boehner (R-OH) was unpersuaded.
Democrats are seeking to highlight Issa's consistently debunked effort to tie the attacks to former Secretary of State Hillary Clinton, who is considered a 2016 presidential front-runner should she decide enter the race. Issa's flimsy claims even drew criticism from Fox News Sunday host Chris Wallace.
"Continuing this reckless pattern of launching wholly unfounded accusations on national television—and racking up more and more Pinocchios in the process—is undermining the credibility of our Committee and the seriousness of our work," the Democrats added.
Issa's numerous investigations of the attack have cost the Pentagon millions of dollars and thousands of hours of personnel time, the Defense Department revealed Tuesday.