A top congressman who plans to grill U.S. Attorney Carmen M. Ortiz over her prosecution of Internet whiz Aaron Swartz tipped his hand on his panel’s looming probe, saying Ortiz’s office was driven by ambition and abused its power when it went after a harmless computer hacker.

“We suspect we know some of it had to do with ambition. Big prosecutions. Smart people being brought down. That’s regrettable. Because the best and brightest in our prosecution, U.S. attorneys, should care about disposing of small cases quickly and big cases properly. And this is not a big case,” Republican U.S. Rep. Darrell Issa said at a Washington, D.C., memorial for Swartz.

“We are going to work out restraints on this kind of abuse in the future,” the California congressman said. “And that restraint will be intended to ensure that harmless acts are treated appropriately. Even if in fact they remain against the law, they have to be treated as harmless acts.”

Issa’s remarks came the same day the Justice Department agreed to respond to pointed inquiries on the Swartz case from the House Committee on Oversight and Government Reform, which Issa chairs. Swartz, the 26-year-old Reddit co-founder and free-information activist, killed himself last month while awaiting trial on charges that he hacked into Massachusetts Institute of Technology networks and stole millions of scholarly articles.

The bipartisan congressional panel fired off a three-page letter to U.S. Attorney General Eric Holder last week demanding a briefing on the Swartz prosecution.

Among the questions the panel raised was whether Swartz’s opposition to the controversial Stop Online Piracy Act factored into the decision to prosecute him; what plea deals were offered; how his case compared to prosecutions of other hackers; and why prosecutors pumped up the indictment and left him facing decades in prison and $1 million in fines.

“The crime and punishment have to fit. Everyone here tonight knows the crime and the punishment did not fit. As our committee investigates it, it’s going to be to try to find out how, and why,” Issa said at the Monday night memorial.

A Justice Department official said the agency is working to set a hearing date; a Beltway source said it could take place within two weeks.

Ortiz has come under heavy fire for her office’s hard-nosed prosecution of Swartz, with critics saying she brushed off concerns he was suicidal and pursued the case even after the owners of the documents backed off.

Issa’s panel includes Bay State U.S. Reps. Stephen F. Lynch and John Tierney. Tierney’s spokesman did not reply to a request for comment. Lynch, speaking last night at a Fall River event, was guarded, saying committee Democrats have pledged to stay silent until they have more details. “We’re just taking in information right now,” the Senate hopeful said. “It’s a tragic situation.”

Lynch said he’s satisfied with Holder’s cooperation.

“They’ve been forthcoming,” he said. “For some people, it’s never fast enough. But it’s been a deliberate and responsive reaction to the inquiry.”