Federal authorities have opened a criminal investigation into whether two immigration officers lied under oath about a shooting in Minneapolis last month, as all charges were dropped against two Venezuelan men.

ICE director Todd Lyons said on Friday that his agency opened a joint investigation with the justice department after video evidence revealed “sworn testimony provided by two separate officers appears to have made untruthful statements” about the shooting of one of the Venezuelan men during the Trump administration’s immigration crackdown across the Minneapolis area.

The officers, who were not named, are on administrative leave while the investigation is carried out, he said. Lyons said the two ICE officers could be fired and face criminal prosecution.

“Lying under oath is a serious federal offense,” said Lyons, adding that the US attorney’s office is actively investigating.

“The men and women of ICE are entrusted with upholding the rule of law and are held to the highest standards of professionalism, integrity, and ethical conduct,” Lyons said.

“Violations of this sacred sworn oath will not be tolerated. ICE remains fully committed to transparency, accountability, and the fair enforcement of our nation’s immigration laws.”

Earlier on Friday, US district court Judge Paul A Magnuson dismissed felony assault charges against Alfredo Alejandro Aljorna and Julio Cesar Sosa-Celis, who were accused of beating an ICE officer with a broom handle and a snow shovel during a January fracas. The officer fired a single shot from his handgun, striking Sosa-Celis in his right thigh.

The cases were dropped after a highly unusual motion to dismiss from US attorney for the district of Minnesota Daniel N Rosen, who said “newly discovered evidence” was “materially inconsistent with the allegations” made against the two men in a criminal complaint and at a hearing last month.

The reversal follows a string of high-profile shootings involving federal immigration agents in which eyewitness statements and video evidence have called into question claims made to justify using deadly force. Dozens of felony cases against protesters accused of assaulting or impeding federal officers have also crumbled.

The immigration lawyer representing Aljorna and Sosa-Celis said they are “overjoyed” that all charges have been dismissed. Had they been convicted, the two immigrants would have faced years in federal prison.

“The charges against them were based on lies by an ICE agent who recklessly shot into their home through a closed door,” said attorney Brian D Clark. “They are so happy justice is being served.”

It is unclear whether the men could still be deported.

Last month, an FBI investigator said in a now-discredited court affidavit that ICE officers attempted to conduct a traffic stop on a vehicle driven by Aljorna on 14 January. He crashed the vehicle and fled on foot toward the apartment duplex where he lived. An immigration officer chased Aljorna who – according to the government – violently resisted arrest.

The complaint alleged Sosa-Celis and another man attacked the officer with a snow shovel and a broom handle as the officer and Aljorna struggled on the ground. The officer, who is not named in court filings, fired his handgun, striking Sosa-Celis. The men ran into an apartment and eventually were arrested.

After the shooting, Kristi Noem attacked Minnesota governor Tim Walz and Minneapolis mayor Jacob Frey, accusing the Democrats of “encouraging impeding and assault against our law enforcement which is a federal crime, a felony”.

“What we saw last night in Minneapolis was an attempted murder of federal law enforcement,” Noem said in a 15 January statement. “Our officer was ambushed and attacked by three individuals who beat him with snow shovels and the handles of brooms. Fearing for his life, the officer fired a defensive shot.”

The Department of Homeland Security did not respond on Friday to questions about whether Noem stands by those statements, which ICE – part of DHS – now admits were false.

Robin M Wolpert, a defense attorney for Sosa-Celis in the criminal case, said she was pleased ICE and the justice department are publicly acknowledging and investigating untruthful statements by the two ICE officers.

“These untruthful statements had serious consequences for my client and his family,” Wolpert said. “My client is a crime victim.”