Democratic New Jersey Gov. Jon Corzine turned up the heat on his Republican opponent, former U.S. Attorney Chris Christie, in a television spot that shows the ex-prosecutor stalking out of a House hearing ^[1] on contracts he awarded as U.S. Attorney.

The attack ad highlights a contract worth up to $52 million that Christie gave to former U.S. Attorney General John Ashcroft to monitor a medical device maker accused of offering kickbacks to doctors. The commercial also draws attention to a monitoring contract to David Kelley, a former U.S. Attorney in Manhattan, who had previously investigated Christie’s brother for stock fraud. Kelley had declined to bring an indictment.

“But when the time came for telling the truth, Christie got up and left,” the announcer said. “Chris Christie. Unbelievable.”

Christie is leading Corzine in the polls. The former U.S. Attorney has the support of 53 percent of likely voters, according to the latest Quinnipiac University poll. The New Jersey governor has the backing of 41 percent of likely voters, the survey said.