Mike Signer, an unsuccessful Democratic candidate for lieutenant governor in 2009, is expected to run for attorney general next year, according to several Democrats familiar with his plans but not authorized to speak publicly.

The Arlington lawyer and former counsel to then-governor Mark Warner (D) launched New Dominion Project, a political action committee and Web site last year.

Signer did not return a call for comment but has been calling Democrats with the news in recent days.

Last month, Sen. Mark Herring (D-Loudoun) started calling supporters to tell them he plans to run for attorney general in 2013.

Possible candidates have been lining up since Attorney General Ken Cuccinelli (R) announced in December that he would not run for reelection, but instead would challenge Lt. Gov. Bill Bolling (R) for governor.

Former House Minority Leader Ward Armstrong (D), who lost his seat after Republicans eliminated his largely rural Southside district, has said he is considering running for attorney general.

At least three Republicans are expected to be in the race: Late last year, Robert Bell (Charlottesville) and Fairfax County Clerk of Court John Frey announced they were running to be the state’s top lawyer. Sen. Mark Obenshain (Harrisonburg) said he will explore running.