Tom Homan, the Trump administration “border czar”, on Sunday said he did not believe the Immigration and Customs Enforcement (ICE) officer at the center of a recent fatal shooting in Maine “should have ever cleared vetting”.

Speaking to CNN’s State of the Union, Homan was asked by host Dana Bash about the officer’s eligibility to serve following reports that two of his ex-wives had accused him of abuse.

“Should someone with those issues be an ICE agent?” Bash asked.

“No, if those … are facts … I don’t think he should ever have cleared vetting,” Homan replied.

Homan also said part of an ongoing investigation into the 13 July shooting death Joan Sebastián Durán Guerrero is determining “how … did the vetting process fail”.

“When they hire somebody, they put them through a vetting process and look at all that stuff. So I know, based on that information – that’s part of the ongoing investigation,” Homan said. “How … did the vetting process fail? Was that information not available? Did they not know?”

He added: “So there’s a separate administrative investigation on what happened here. Did we have that information? Did we not have that information? But the vetting process … if that was factual, he would have an almost impossible time to pass vetting.”

The officer involved in the killing of Durán Guerrero, a 25-year-old Colombian man in Biddeford, Maine, has since been identified by news outlets as David Brouillette. The US Department of Homeland Security (DHS), which oversees ICE, has not publicly confirmed Brouillette’s identity.

Since the shooting, two of Brouillette’s ex-wives have publicly described alleged abuse during their relationships with him. One, Lucinda Brouillette, alleged her ex-husband engaged in a “persistent pattern of abuse, intimidation, manipulation, fear and control”.

“If you were to ask me whether I believe David Brouillette is capable of this level of violence, my answer is unequivocally yes,” she said in a statement to NPR.

Although Homan declined to comment directly on this particular case, describing it as “a rare instance”, he said: “If this person had that type of history, it would have been a vetting issue, and it should have been brought to the attention of those who make those decisions.”

He added, in part: “We will see. It’s all being reviewed. We will see where it lies.”

The shooting has prompted renewed scrutiny of ICE’s hiring practices.

Democrats have called for reviews of the agency’s vetting process. For instance, Mississippi congressman Bennie Thompson, the top Democrat on the US House homeland security committee, said that Brouillette’s alleged abusive past “directly call[s] into question the supposed vetting and training ICE does of its recruits”.

Neither the fatal shooting in Maine nor another one involving an ICE officer in Texas earlier in July yielded body camera footage from officers. That prompted Homan to announce that the agency would require officers to wear body cameras during vehicle stops.

In the Texas case, which resulted in the killing of Mexican national Lorenzo Salgado Araujo, the Harris county district attorney Sean Teare said in a statement that lab results of a white substance found in a van at the center of a case tested negative for narcotics or illicit drugs – despite an FBI search warrant application that maintained a bag with substance in question was consistent with methamphetamine.

Salgado’s family had said the substance was a salt mixture that he and his construction crew colleagues used as electrolytes to stay hydrated in extremely hot temperatures.