Raleigh, N.C. — The same day he officially became a candidate for governor, State Treasurer Richard Moore took a swipe at his main rival for the Democratic nomination by suggesting Lt. Gov. Beverly Perdue gained financially by backing a bridge project a decade ago.

An online campaign ad had hammered Perdue in recent weeks for her support of the $120 million Neuse River Bridge in her hometown of New Bern in the late 1990s. Moore stepped up the attack Tuesday, however, by citing a 150-acre residential development that Perdue co-owned and that profited once the span was completed.

"A very powerful insider has to be very careful on how they make their money," said Moore, who filed his candidacy paperwork with the State Board of Elections Tuesday afternoon. "This is the reason we need (state Department of Transportation) reform. This is the reason why we don't need politicians making these kinds of decisions behind closed doors on where our road dollars get spent."

Perdue campaign spokesman David Kochman said the Neuse River Bridge project had widespread local, state and federal support. Perdue, who was in the state Senate at the time, wasn't motivated by making money off her real estate holdings, he said.

"Fighting for that bridge is exactly what she should have been doing because the old bridge was twice as dangerous as the bridge that collapsed in Minnesota," Kochman said.

An Interstate 35 bridge over the Mississippi River in Minneapolis collapsed last August, killing 13 people and injuring dozens more.

"Everybody benefited from that bridge," Kochman said, calling Moore's suggestion "an attempt to score cheap political points."

Moore, who has pushed for more chances to debate Perdue, said he would welcome the chance to discuss the issue with her.

"If it's a cheap shot, let's talk about it," he said.

So far, many political watchdogs said they don't see a scandal in Perdue's support for the bridge project.

"I just don't see this being a clear-cut case of a public official using their office for personal financial gain," said Bob Phillips, executive director of Common Cause North Carolina.