WASHINGTON - The Office of Congressional Ethics is turning over evidence to the Justice Department that suggests some defense contractors thought their campaign donations were influencing the award of special-interest projects, the ethics office announced Thursday.

The move by the ethics office's board focused renewed attention on the politically sensitive subject of congressional earmarks. It also was a slap at the House ethics committee, which concluded early this year that the evidence did not support a finding that any House member broke a law or regulation.

Since 2008, the Justice Department has been investigating members of the House Appropriations defense subcommittee who received a flood of campaign money over the years from the lobbying firm PMA Group and its defense-contractor clients.

The subcommittee had been chaired by Rep. John P. Murtha (D., Pa.), who died in February. PMA, founded by a former Murtha aide, went out of business after the FBI raided its offices.

Conducting its own examination of Murtha and six other subcommittee members who took money from PMA's clients, the ethics office zeroed in on Reps. Pete Visclosky (D., Ind.) and Todd Tiahrt (R., Kan.).

The ethics office concluded there was reason to believe that Visclosky solicited contributions in exchange for official acts. The office's investigation found that in Tiahrt's case, there were potential connections between appropriations requests from PMA clients and the clients' campaign donations to Tiahrt.

The House ethics committee reviewed the evidence on Visclosky and Tiahrt and closed its inquiry without acting against either man nor against any of the other five subcommittee members.

The ethics committee's inaction seemed to end the matter. But Reps. Jeff Flake (R., Ariz.) and Paul Hodes (D., N.H.) asked the ethics office to publicly release its evidence. The office's board declined, saying that would undercut an ongoing criminal investigation, but it voted instead to forward its material to Justice for use in the probe.

It did not identify which members of Congress the evidence involved.