Lawyers for a Washington lobbying firm have asked federal prosecutors to investigate a former employee who the firm says sent fake letters to members of Congress urging them to oppose climate change legislation. A spokesman for the firm, Bonner & Associates, said the request was dated Aug. 12, adding that the firm's owner, Jack Bonner, 'is quite serious about prosecuting this individual and making sure he doesn't do this again.' The fake letters, which appeared to be from nonprofit groups that had no idea their logos and names were being used, have incited greater scrutiny of 'astroturfing,' a tactic used by professional lobbyists to make their efforts appear to be part of grass-roots movements. Rep. Edward J. Markey, D-Mass., who was a co-sponsor of the climate-change legislation, has investigators from the Select Committee on Energy Independence and Global Warming looking into the tactic as part of an inquiry into the fake letters. Bonner & Associates had been hired by another lobbying firm, the Hawthorn Group, which was working on behalf of the American Coalition for Clean Coal Electricity. The coalition paid Hawthorn roughly $1 million in the first six months of 2009 to seek changes in the climate change legislation, the American Clean Energy and Security Act, according to a letter it sent to the congressional committee. Hawthorn, in turn, spent some of that money to pay Bonner for the campaign that included the fake letters. Hawthorn also paid Executive Communications, a company in Louisville, Ky., to mobilize the 225,000 members of America's Power Citizen Army, an organization financed by the coal trade group, in opposition to the legislation. More than 4,000 calls were made by Citizen Army members to members of the House of Representatives from June 24 to June 26, when the House voted on the bill, according to the coalition's letter. Joe Lucas, senior vice president for communications at the coalition, said Executive Communications staff members had called members of the Citizen Army as the climate bill moved through Congress to enlist their help in persuading House members to push for changes and express their opinions. He rejected the contention that the phone effort was 'astroturfing.' 'This is the truest form of grass-roots there is,' Lucas said. 'We don't charge people to be members of the Citizen Army, so if anything, it's more organic than what some of the environmental groups do. We allow these people to express their own opinions on these issues.' 