Washington (CNN) -- He is best known as the Viper car alarm voice that instructs would-be thieves to "Please step away from the vehicle."
But in political circles, Rep. Darrell Issa, chairman of the House Oversight and Government Reform Committee, is a man who, after years of sounding the alarm about perceived Obama administration misdeeds, has struck a chord that is shaking up Washington.
The California Republican has the White House on the ropes trying to explain its handling of the deadly terror attack on the U.S. diplomatic mission in Benghazi, Libya, last September and IRS targeting of conservative groups seeking tax-exempt status.
During a hearing on Wednesday, Issa's committee was prepared to zero-in on whether the White House was informed about IRS targeting.
Issa dismissed IRS official Lois Lerner, who heads the division that manages tax-exempt applications, after she invoked her constitutional right against self-incrimination and indicated she would not answer questions.
"We will take your refusal as a refusal to testify. The witness and counsel are dismissed," he said.
The impact of ongoing investigations by Issa's committee is largely dependent on what is unearthed.
However, Issa has emerged as a high-profile player in a political showdown with potential implications for the tenor of President Barack Obama's second term and the 2016 presidential election.
"They may have been laughing before, but they aren't laughing now," said former Virginia Republican Rep. Tom Davis of previous Democratic scoffing at Issa's multi-year hunt for White House impropriety under Obama.
"Everyone underestimated Darrell," said Davis, a longtime Issa friend and mentor. "They learned. He is very smart."
Tech wiz turned political enforcer Outside the Cannon office building on Capitol Hill, the early February air was chilly with forecasts of flurries.
Inside, the mood was somber as Issa and other lawmakers paid their respects to Aaron Swartz, a young Internet activist and co-developer of RSS and Reddit who had hanged himself a month earlier in his Brooklyn apartment.
Swartz was considered something of a troubled prodigy — an Internet savant and dot-com millionaire who battled legal problems and depression.
On the day of the memorial, the microphones weren't working properly and Issa, an electronics whiz and businessman who also faced legal troubles in his youth, quickly stepped up to help solve the problem, according to friend Gary Shapiro, CEO of the Consumer Electronics Association, who attended the event.
"He has quite a bit of a following among the netizens of the world," Shapiro said of Issa, who has publicly opposed congressional efforts to curb copyright infringement by restricting access to sites that host or facilitate the trading of pirated content.
Issa, and other opponents, worry about government overreach and censorship.
"'Stick it to the man,' something from my generation, resonates with everyone here tonight," Issa said during Swartz's memorial. "Ultimately, trusting a government is inconsistent with our founding words, 'We the people. Aaron understood that ..."
Two years before, when Issa took over as chairman of the Oversight panel, he quickly set his sights on investigating everything from the Justice Department's handling of the botched "Fast and Furious" gun-running operation to the impact of the Obama administration's green energy agenda on job creation.
He helped launch dozens of investigations with varied success.
In 2010, Issa told conservative radio host Rush Limbaugh that Obama "has been one of the most corrupt presidents in modern times."
Since then, Issa's investigations, especially involving the Justice Department, have led to a contentious relationship with Attorney General Eric Holder.
In particular, Issa led an effort last year to cite Holder for contempt of Congress in his committee's probe of "Fast and Furious."
Holder called Issa's behavior "unacceptable" and "shameful" during a recent House Judiciary Committee meeting when the lawmaker accused him of politically motivated stall tactics over the delayed release of private e-mails of a top Holder aide.
Some Democrats feel Issa is on a witch hunt.
Donna Brazile, former head of the Democratic National Committee and a CNN contributor, recently questioned whether Issa's Benghazi hearings were used by the GOP as "an opportunity to smear Obama, sabotage (former Secretary of State Hillary Clinton) and fund raise like giddy televangelists."
Ranking House Oversight Committee Democrat Rep. Elijah Cummings, D-Maryland, raised similar concerns during recent Benghazi hearings.
"Chairman Issa has accused the administration of intentionally withholding military assets which could have helped save lives on the night of the attacks, I say, for political reasons," Cummings said. "Of all the irresponsible allegations leveled over the past two weeks, this is the most troubling. And based on what our military commanders have told us, this allegation is simply untrue."
Issa has said he is motivated not by politics but by an interest in government transparency.
The people's investigator Issa seems acutely aware of his moment in the spotlight.
During the dramatic build up to the Benghazi hearings, his committee posted a series of movie promo style photos to its Flickr account. The words "Exposing Failure ... Recognizing Courage" are highlighted in blue and white against the shadowy backdrop of an empty congressional hearing room.
"The leadership fought him on Benghazi and he came out of this where he's got the administration swinging," Davis said.
For his part, Issa sees himself as the people's investigator—a role he is clearly savoring.
"From both my time in the private sector and in Congress, the power of telling the public the truth can't be overstated," Issa told CNN in a statement. " What happened in Benghazi and at the IRS is too important for us not to fully examine. The public demands and deserves answers."