They’ve been described as law enforcement twins and “brothers in arms.”

#COMEY & #Mueller were brothers in arms in famous 2004 standoff over domestic surveillance. Cagey choice by DAG Rosenstein. — Jim Sciutto (@jimsciutto) May 17, 2017

Once again, James Comey and Robert Mueller — two respected FBI veterans — have found themselves sharing the same high-profile headlines.

The two men’s working relationship can be traced back to at least December of 2003, when Comey joined Mueller in Washington after he became John Ashcroft’s deputy attorney general, according to a 2013 Washingtonian article about the two men’s long0standing relationship.

“He and Mueller spent many hours together, developing a close partnership — and watching together the disarray in the government over how to respond to the unfolding war on terror,” Washingtonian notes. “They shared a horror at the poor quality information infiltrating the upper reaches of government.”

The article goes on to point to personal similarities as well as professional. Both men were educated at Virginia universities — Mueller at the University of Virginia, Comey at William & Mary.

“Just years apart in the 1990s, they both gave up their top-tier private law firm jobs to return to the trenches of prosecuting criminals — Mueller as a junior prosecutor in Washington, DC, and Comey in Richmond, Virginia,” Washingtonian reports. “Both men were rising stars mentored and guided by Eric Holder in the 1990s during Holder’s time in the Justice Department under the Clinton administration.”

Their relationship was made stronger during an incident in 2004. At the time, the Los Angeles Times reported, Comey, Mueller and a number of other law enforcement officials were on the verge of resigning in opposition to a Bush administration plan to reauthorize a domestic surveillance program that was launched after the terror attacks of 9/11. President Bush eventually agreed to modify the secret program after both men jointly intervened — an experience that is suspected to have drawn them even closer.

This week — amid allegations that President Trump pressured Comey to drop a probe into former national security adviser Michael Flynn — the ousted FBI director’s associates have praised his truthfulness and credibility.

It’s a quality that many Republicans and Democrats believe Comey shares with Mueller, his predecessor.

“Regardless of your chosen career, you are only as good as your word,” Mueller told William & Mary’s graduating class in 2013. “You can be smart, aggressive, articulate, and indeed persuasive. But if you are not honest, your reputation will suffer. And once lost, a good reputation can never, ever be regained.”