This post has been updated.

Republican presidential candidate Rick Santorum’s campaign is taking aim at rival Mitt Romney’s tenure at the helm of Bain Capital.

The ramped-up criticism by the Santorum camp of Romney’s business record comes on the eve of the key Illinois primary. It also comes two months after Santorum defended Romney from similar attacks by former House speaker Newt Gingrich (R-Ga.) and Texas Gov. Rick Perry (R) in the run-up to the South Carolina primary.

Here’s Santorum senior adviser John Brabender in an interview on MSNBC Monday (video courtesy of The Page).

“When Mitt Romney was at Bain Capital, almost one out of every four companies that they were involved in either went bankrupt or out of business,” Brabender said.

At a Monday morning campaign event, Santorum himself criticized Romney as a “Wall Street financier,” reports Politico’s Juana Summers:

“I heard Governor Romney here called me an economic lightweight because I wasn’t a Wall Street financier like he was,” Santorum told several hundred supporters at a Rockford, Illinois rally. “Do you really believe this country wants to elect a Wall Street financier as the president of the United States? Do you think that’s the experience that we need? Someone who’s going to take and look after as he did his friends on Wall Street and bail them out at the expense of Main Street America.”

Taken together, the remarks by Santorum and Brabender suggest a new twist in the former Pennsylvania senator’s strategy – and a departure form Santorum’s earlier position on his GOP rival’s background in venture capital.

Back in January, when Perry and Gingrich were hitting the former Massachusetts governor hard on his Bain tenure, Santorum had told CNN’s Wolf Blitzer, “I hate to sit here and be a defender of Mitt Romney, but to me this is federal capitalism, and I have to say that this is an attack probably not warranted.”

“Bain Capital, at least from the record I looked at, had a lot of success,” Santorum said at the time. “I mean they weren’t a company that has a long track of record basically destroying the companies and selling off the pieces. They had some situations where they had failures but every company does.”

Said Romney spokeswoman Andrea Saul: “It used to be that Sen. Santorum stood up for free enterprise and the private sector when desperate politicians went on the attack.

“Sadly, he has decided to join the assault on free enterprise in a way usually reserved for liberals,” Saul said. “There’s a reason he hopes the economy isn’t the ‘real issue’ in this election: he knows that we’re not going to turn around this economy by replacing one former senator with zero job-creating experience with another senator with zero job-creating experience.”