COLUMBUS, Ohio -- Ohio Secretary of State Jennifer Brunner has launched an investigation into who is funding a conservative group pushing a ballot measure aimed at blocking horse racing tracks from getting slot machine gambling.

Brunner announced today that she has issued subpoenas to the principals behind LetOhioVote.org and its shadowy, sole funding source, New Models, a Glen Allen, Va.-based corporation.

"The law is clear that what is spent for proposed ballot issues must be reported," Brunner, a Democrat, said in a statement. "Using a 'straw person' out-of-state corporation to hide the real sources of funding not only violates the public trust, it looks like concealment, which is against the law."

LetOhioVote was created by former Cincinnati-area Republican state Rep. Tom Brinkman. Columbus-area consultants Gene Pierce and spokesman Carlo LoParo have also represented the group.

LoParo called Brunner's inquiry a "fishing expedition."

"LetOhioVote has fully complied with all campaign finance laws," LoParo said today. "It is pretty clear this is a fishing expedition that most certainly will waste taxpayer dollars and time."

LetOhioVote was created after Gov. Ted Strickland last year proposed allowing 17,500 slot machines at Ohio's seven racetracks to develop a new source of revenue for the cash-strapped state budget.

The group sued the governor, and the Ohio Supreme Court sided with LetOhioVote, saying Strickland could not add slots unless a voter referendum was called. LetOhioVote then launched an effort to do just that, put the issue on the November ballot, which all but killed the governor's immediate plans for fiscal relief from this form of gambling.

LetOhioVote had repeatedly dodged questions about where its funding is coming from. And when the group did finally have to file a campaign finance report to the state, it claimed all $1.55 million of its cash came from one source -- New Models.

New Models was formed to engage in political activities but is required only to file reports with the Internal Revenue Service.

It was behind controversial automated calls to Pennsylvania voters made during the 2008 presidential election. The calls told voters that Barack Obama's aunt was living in America illegally and that he accepted campaign contributions from his "illegal alien aunt," according to a transcript of the call posted on Politico.com.

Tim Crawford is president of New Models. He raised money for former Ohio Republican gubernatorial candidate Ken Blackwell's 2006 campaign. Pierce and LoParo also worked on Blackwell's campaign that year.

"Voters are being asked to pay for a statewide election on a ballot issue for November that will increase the length of the ballot and subject voters to all kinds of advertising," Brunner said. "The least we can do is require those behind the effort to say who they are, like campaign finance laws require. The public has a right to know."

Those issued subpoenas include Brinkman, LoParo, Pierce, Crawford and Norman Cummings, of Lancaster, Va., a former Blackwell campaign consultant who set up the LetOhioVote.org domain name, according to the secretary's office. Brunner also issued subpoenas to LetOhioVote and New Models as organizations. The secretary is asking each to submit to a deposition and to produce certain records.

While LoParo has acknowledged knowing Crawford, it is still unclear why a Virginia-based corporation would be so interested in an Ohio initiative that it would be the only funding source. Also, unclear is where New Models gets its money that it then uses to fund political activity around the country.

New Models has not returned calls for comment.

LoParo said that because of the subpoena, he was forbidden by LetOhioVote lawyers to comment about the relationship between his group and New Models.

Ohio voters last November passed a constitutional amendment that will allow four full-service casinos to be built in the state, including one in Cleveland by Cavaliers majority owner Dan Gilbert. The first casino is expected to open in late 2012.

But under the governor's proposed plan, the slots would have been at racetracks as early as this spring.