Concerns over the IRS scandal shows no signs of dimming as new developments push Republicans to use the controversy as political fodder, and as campaign season falls upon us, some are using the incident as a catalyst for their own reelection.

According to attorneys, there is evidence of more letters targeting conservative groups that originated from other IRS locations outside of the Cincinnati, the original location under fire.

And at least one of those letters had the signature of former director of the IRS Exempt Organizations department in Washington, Lois Lerner, NBC reports.

This recent development goes against the original testimony of IRS executives who first testified that the scandal went no further than a few "front line" employees in the Cincinnati office.

"We've dealt with 15 agents, including tax law specialists - that's lawyers - from four different offices, including (the) Treasury (Department) in Washington, D.C.," said Jay Sekulow, an attorney representing 27 conservative groups involved. "So the idea that this is a couple of rogue agents in Cincinnati is incorrect."

Sekulow provided NBC with some of the letters and they are reporting that, "Among the letters were several that bore return IRS addresses other than Cincinnati, including 'Department of the Treasury / Internal Revenue Service / Washington, D.C.,' and the signatures of IRS officials higher up in the chain."

The scandal first got attention last year when conservative groups reached out to lawmakers complaining of harassment, siting unorthodox requests for attendance lists, combined with requests like donor lists and meeting(s) information.

In the weeks following admittance and testimonies from IRS spokespeople and executives, Republicans seeking reelection have begun using the events as fuel against the White House.

In a recently released campaign ad, Senate Republican Leader Mitch McConnell uses archived footage of Ricard Nixon to support his attack against President Obama and his administration.

ABC News obtained the online ad that has posed the questions to Americans: "What don't they want us to know?"

The ad also pushes a voice recording of former president Nixon declaring: "When the president does it, that means it's not illegal."

Watch the entire ad here: