(CNN) -

Rep. Darrell Issa said Sunday the committee he chairs will "probably never know" if a computer crash that destroyed sought-after emails was a deliberate act to cover up wrongdoing at the IRS.

In an exclusive interview with CNN's Candy Crowley, the California Republican said that though the hard drive belonging to former IRS official Lois Lerner is "physically gone," there's evidence that she was in violation of some agency regulations.

"What we do know from the discovery we have gotten from emails, that we've gotten from multiple sources, is she broke some regulations. She broke some laws," he said. "She sent, trying to get prosecution apparently, she sent 1.1 million tax records over to the Department of Justice including inappropriate or actually illegal... disclosures on behalf of conservative groups."

Lerner resigned last year after the Treasury Department's inspector general found people working under her used "inappropriate" criteria to scrutinize certain groups, particularly those with conservative political names, that had applied for tax-exempt status. The House Oversight and Government Reform Committee, which Issa chairs, is investigating.

The computer crash, the latest turn in the already convoluted investigation, has further inflamed Republican suspicions that Lerner has something to hide.

"Obviously she had 30 years of experience," Issa said. "She knew under the federal records act that she had an obligation for these documents to be preserved, these emails. And to not have print to paper, which is the policy that she had to know, is pretty hard to believe -- that there aren't paper copies."

Issa continued: "So do I believe that she printed to paper? Yes. She's an attorney of long standing and it's kind of hard to believe that you wouldn't cover with your own paper copies."

The committee chairman also went after Lerner's attorney, William Taylor, after his client refused to testify at hearings, invoking her constitutional right not to do so.

"Her attorney has said things that are not correct, or disingenuous or outright lied a number of times, it's been shown by emails," Issa said.

"(An) attorney trying to get his client off the hook after flubbing and taking the Fifth certainly will say and do a lot of things."

The IRS failure to keep proper documentation and backup communication, Issa said, "has very little to do with the fundamental problem, which is (that) Lois Lerner's unit, headed by Lois Lerner and directed by Lois Lerner, unfairly targeted and abused conservative groups for what they believed."

Democrats, meanwhile, as well as Lerner's attorney, accuse House Republicans of politicizing the investigation, noting that some liberal groups seeking tax-exempt status also apparently were targeted by the agency.

In his first television appearance on the controversy, Taylor wouldn't respond specifically to Issa's claim that he had lied, but suggested Republicans are using his client has a political tool to gin up conservative enthusiasm ahead of the midterm elections.