"Hannity" host Sean Hannity reacted to Justice Department Inspector General (IG) Michael Horowitz's testimony about the origins of the Russia investigation and asked what former President Barack Obama's role was in the probe.

Hannity joined Mark Levin for an interview airing Sunday at 8 p.m. ET on "Life, Liberty & Levin" and told the constitutional attorney and radio host that the former president must have had knowledge of the 2016 investigation.

"I want to know what Obama -- what did you know and when did you know it?" Hannity said. "Because as your friend [former federal prosecutor] Andy McCarthy will say, 'You can't have a counterintelligence investigation without it starting with the president in the Oval Office.'"

Hannity recalled how the FBI utilized an unverified and discredited "Russian" dossier of salacious claims about President Trump to obtain a warrant to surveil a member of his campaign staff, Carter Page. Page previously disclosed to Hannity that he had been a confidential source for the CIA, and not in cahoots with the Russian government as claimed.

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Hannity said the texts between ex-FBI Agent Peter Strzok and former FBI lawyer Lisa Page shed light on the likelihood that Obama knew the federal government was using a flimsily-compiled dossier as a pretext to surveil a member of a presidential campaign from the opposing political party.

"I will guarantee you it goes into that Oval Office because there was a line in the Strzok-Page texts: 'The White House wants to be informed every step of the way.' Very telling," Hannity said.

"Just like the 'insurance policy.' Just like 'Hillary should win 100 million to 0,'" he continued, referring to messages in which Strzok and Page detailed their aversion to Trump. "There's a lot to dissect from all of that."

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The dossier, compiled by former MI6 agent Christopher Steele, was paid for by Fusion GPS -- an opposition research firm utilized by the Hillary Clinton campaign, Hannity said.

In addition, Hannity said, many in the mainstream media have turned the institution into "State TV" in that they offer one-sided coverage that places President Trump and Republicans in a negative light.

"When you get to the bottom of all of this, you see corruption... lying and smears, slander, besmirchment, character assassination and outright State TV," he said. "The danger in this is black is white, white is black, up is down, down is up -- and it's sort of like a '1984' scenario here where people that do tell the truth [get] excoriated."

Despite this, Hannity said he believes most of the American electorate sees past the reporting and will have the "final say" in November 2020.