The founders of opposition research firm Fusion GPS, which commissioned Christopher Steele to compile intelligence reports about President Donald Trump's ties to Russia, said what the former British spy discovered "shocked us."

In a commentary for The New York Times posted Tuesday, former Wall Street Journal reporters Glenn Simpson and Peter Fritsch blasted congressional Republicans for "chasing rabbits" amid a growing criminal inquiry into Russian meddling in the presidential election.

The pair asserted they hired Steele "without informing him whom we were working for and gave him no specific marching orders beyond this basic question: Why did Mr. Trump repeatedly seek to do deals in a notoriously corrupt police state that most serious investors shun?"

The compilation by Fusion was reportedly paid for by the presidential campaign of Hillary Clinton and the Democratic National Committee.

"What came back shocked us," they wrote.

"Mr. Steele's sources in Russia (who were not paid) reported on an extensive — and now confirmed — effort by the Kremlin to help elect Mr. Trump president. Mr. Steele saw this as a crime in progress and decided he needed to report it to the F.B.I."

The pair said they didn't discuss Steele's decision with anyone, deciding instead to defer to the ex-British spy, whom they described as "a trusted friend and intelligence professional with a long history of working with law enforcement."

"We did not speak to the F.B.I. and haven't since," they wrote.

"We're extremely proud of our work to highlight Mr. Trump's Russia ties," they added. "To have done so is our right under the First Amendment."

"It is time to stop chasing rabbits," they wrote. "The public still has much to learn about a man with the most troubling business past of any United States president. Congress should release transcripts of our firm's testimony, so that the American people can learn the truth about our work and most important, what happened to our democracy."