FIRST ON FOX: A group of Republican senators on Wednesday urged the Department of Homeland Security (DHS) to release its findings from the probe into Border Patrol agents who were at the center of false claims that they "whipped" Haitian migrants.

"We agree that the public deserves to know the results of this investigation," the lawmakers, led by Sen Bill Hagerty, R-Tenn., wrote in a letter to DHS Secretary Alejandro Mayorkas.

PROBE INTO BORDER PATROL AGENTS STILL ONGOING, 6 MONTHS AFTER FALSE ‘WHIPPING’ CLAIMS 

"Yet, it has been more than six months since this episode occurred, and no report has been released," they say.

The other senators on the letter are Sens. Ted Cruz, R-Texas, John Cornyn, R-Texas, Kevin Cramer, R-N.D., Josh Hawley, R-Mo., Tommy Tuberville, R-Ala., and Mike Lee, R-Utah.

The investigation centered around agents on horseback who in September attempted to block Haitian migrants from entering the U.S. via a river in Del Rio, near a massive migrant camp. The controversy began when some media outlets and Democratic lawmakers misidentified the agents’ split reins, which they use and twirl to control and direct the horse -- and falsely claimed the agents were using "whips" on the migrants.

Mayorkas initially backed the agents alongside Border Patrol Chief Raul Ortiz, but later said the images "troubled me profoundly" before adding that "one cannot weaponize a horse" against migrants. Vice President Kamala Harris also weighed in, saying she wanted an investigation and was "deeply troubled" about the alleged treatment of migrants.

Border Patrol agents

Mounted U.S. Border Patrol agents watch Haitian immigrants on the bank of the Rio Grande in Del Rio, Texas on Sept. 20, 2021. (John Moore/Getty Images)

Shortly after that, Mayorkas announced that horses would no longer be used in Del Rio, and the agents were shifted to desk duty pending an investigation into their conduct. He would go on to promise that the investigation would be "completed in days, if not weeks."

That Friday, President Biden increased the pressure on the agents by repeating the whipping claims, and also previewed what he hoped would be the outcome of the investigation.

"To see people treated like they did, horses barely running over, people being strapped – it's outrageous," Biden said, making a whipping motion with his hand

"I promise you, those people will pay," he said "There will be an investigation underway now and there will be consequences. There will be consequences."

The Republican letter says that the administration "very publicly and harshly condemned this patrol activity" even before the facts were gathered.

Six months later, the investigation is still ongoing. A DHS spokesperson told Fox last month that the agency "will share the results of the investigation once it is complete and provide updates, as available, consistent with the need to protect the integrity of the investigation and individuals’ privacy."

BORDER PATROL STUNNED AS BIDEN GOES TO WAR WITH HIS OWN AGENTS OVER FALSE ‘WHIPPING’ ALLEGATIONS

The spokesperson referred to an update from November, which outlined how the matter had been referred to the Office of Inspector General -- which declined to investigate and instead referred it to Customs and Border Protections (CBP) Office of Professional Responsibility -- and the steps that are to be taken.

But the lengthy investigation has led to accusations that the investigation is being lengthened for political reasons. The head of the Border Patrol Union recently told Fox News Digital that he thinks "they're trying to drag this out and get the American public to forget about it because ultimately they're going to have to come back and say [the agents] did nothing wrong, or they're going to have to make some charges up and try to fit some charges under policy."

A DHS official who spoke to The Washington Examiner in January shared that assessment, and even questioned whether the administration would ever release the report. 

"I doubt that the current administration will release this report on the horse patrol incident because it makes the administration look terrible," the official said. "They essentially convicted the mounted agents based upon a lie, which the investigation after 120 days would surely have revealed."

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The Republicans say that "it remains unclear why these findings have not been released."

"The American people—and especially your agents whose superiors publicly accused them of misconduct—deserve the transparency you promised, even if it is embarrassing for the Biden administration," they say.

The lawmakers request that the findings of the investigation be released by April 13.