BOSTON -- The four gubernatorial candidates for governor squared off in a televised debate Monday night, with independent Christy Mihos playing the spoiler, steering the argument toward Big Dig cost overruns and illegal immigration.

NewsCenter 5's Gail Huff reported that the format of the debate allowed the candidates to spar with each other, and one of the liveliest exchanges concerned the controversial $14.6 billion Big Dig.

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Mihos implied that the Romney-Healy administration was responsible for problems that have plagued the Massachusetts Turnpike Authority project that began in the early 1990s, making accusations aimed at Republican incumbent Lt. Gov. Kerry Healy.

"You ran away from your responsibility," Mihos, a former Turnpike Authority board member, said to Healy, not allowing her to respond. "I gave you the documents and you people did nothing with it."

The other candidates, Democrat Deval Patrick and Green-Rainbow candidate Grace Ross, jumped in, making it three against one as they debated education, immigration and tax issues.

"We need to face the fact that we've been playing a fiscal shell game with this administration. This is an adminstration that talks about rolling the income tax back and is responsible at the same time for proposing $985 million in new taxes and increased fees," Patrick said.

"And anybody at the state level who wants to argue that you're not raising taxes because you're rolling back the income tax is just not telling the truth," Ross said.

Mihos was the pit bull that wouldn't butt out, however, echoing his latest political attack ad that portrays Beacon Hill politicians as cartoons with their heads in their posteriors. No matter how much Healy tried to ignore her former fellow Republican, Mihos continued to dominate the exchanges with questions about the administration's record.

"Let me ask you a question, Kerry. How many corporations ... everybody knows illegal immigrants are working here in the commonwealth. How many corporations, under your administration, have you been out there, have you fined, have you gone in and done an investigation? How many of these corporations, how much have you fined them and how many corporations have you looked at?" Mihos asked.

"It's good that you ask that question. We have been urging the attorney general [Reilly] to do that. That is his job as attorney general, to get in there to do that, and we've been asking him to do that," Healy said.

"So, zero," Mihos responded.

With Mihos in the middle, Healy found it nearly impossible to debate Patrick one-on-one.

"I feel great, I really do. You know, I've been waiting for this for a long time to tell the story, and to, you know me, I'm not reticent at all, I speak truth to power, and I'm glad we're getting this all out. I just feel wonderful," Mihos said.

If Mihos' goal was to be noticed, he may have succeeded, but it remains to be seen whether voters liked what they saw. The candidates have agreed to at least two more debates.