The criminal referral suggests the US Attorney's Office charge McCabe with lying to federal investigators.
News of the referral, which was reportedly filed some time ago, comes after the Office of the Inspector General (OIG) released its report last week noting that McCabe "lacked candor" when discussing his decision to authorize disclosures to the media regarding the FBI's investigation into former Secretary of State Hillary Clinton and the Clinton Foundation.
Hours after reports surfaced of the criminal referral being issued, US President Donald Trump chimed into the conversation by taunting former FBI Director James Comey and McCabe.
The OIG's report stated: "We therefore concluded that McCabe's disclosure of the existence of an ongoing investigation in this manner violated the FBI's and the department's media policy and constituted misconduct."
Referrals are non-binding, and it's unclear if the US Attorney's office has proceeded any further, The Hill reported.
Once Horowitz concluded that McCabe had not been truthful with internal investigators on the matter, the FBI Office of Professional Responsibility recommended to US Attorney General Jeff Sessions that McCabe be fired. The 50-year-old Connecticut native was then fired by Sessions two days before he was set to retire from the agency.
Following his dismissal, McCabe stressed that he was "being singled out and treated this way because of the role I played, the actions I took and the events I witnessed in the aftermath of the firing of James Comey," referring to Trump's controversial decision to sack the FBI chief not long into his tenure in the Oval Office.
"This attack on my credibility is one part of a larger effort… to taint the FBI, law enforcement and intelligence professionals more generally," McCabe said in a statement obtained by Reuters. "It is part of this administration's ongoing war on the FBI and the efforts of the Special Counsel investigation, which continue to this day."
Prior to the Thursday revelation, a group of 11 Republicans from the US House of Representatives issued a letter to the Justice Department and the FBI that called for a criminal investigation into McCabe on Wednesday.