The Maryland Board of Elections has asked state Attorney General Doug Gansler to investigate whether Montgomery County needs to disclose its spending on advertisements urging voters to uphold a county law scaling back the police union's bargaining rights.

The county's Office of Public Information has spent roughly $6,000 from its own budget on campaign posters, fliers and ads on the side of Montgomery County Ride On buses, and is using staff time and the county's website for the cause, according to Director Patrick Lacefield.

The ads, unlike other campaign ads, are not subject to the state's campaign finance reporting requirements, county officials say.

After receiving complaints from the Fraternal Order of Police, the Board of Elections asked Gansler for a second opinion, according to Jared DeMarinis, the agency's director of candidacy and campaign finance.

Gansler's spokesman, David Paulson, said he could not comment since the board had made no formal request for an opinion and any advice Gansler offers is protected by attorney-client privilege.

The Montgomery County Council repealed the union's right to "effects bargaining" in summer 2011. When the law took effect, the FOP lost its ability to bargain any management decision that had an effect on union members, including the way equipment is distributed or a change in officers' shifts.

The county can use taxpayers' money for its advertising efforts because it is protecting an existing county law, Lacefield said, citing an opinion by County Attorney Marc Hansen.

"There's no obligation for the county to remain silent while special interests spend hundreds of thousands of dollars to try to misrepresent an issue," Lacefield said. Hansen could not be reached for comment.

But the Fraternal Order of Police has called the spending "apparent gross misconduct" by the county. A few weeks ago, union attorney Lanny Davis pointed to county lawmakers' criticisms when County Executive Ike Leggett's administration spent taxpayer dollars campaigning for an ambulance fee, which was on the ballot in 2010.

The union also asked county Inspector General Edward Blansitt to investigate the matter. Blansitt declined, again pointing to Hansen's opinion that the county was within its rights.

The Fraternal Order of Police, which has contributed more than $35,000 to defeat the measure, has not advertised anywhere yet, though it plans "a heavy push," said spokeswoman Eleanor McManus.