Maricopa County Sheriff Joe Arpaio on Thursday fired back at critics of his years-long questioning of President Obama's birth certificate as he brought an end to his investigation.

Arpaio, a vocal supporter of President-elect Donald Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE who lost his reelection bid in Arizona in November, used a news conference Thursday to complain that his claims about Obama were dismissed.

“We and anyone else who dared to question the document have been maligned, falsely labeled and grossly criticized,” Arpaio said during a news conference in Phoenix, according to The Associated Press.

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The AP reported that Arpaio closed his investigation Thursday after pushing his "birther" conspiracy theory for more than five years.

Under pressure from those questioning Obama's birthplace of Hawaii, including Trump, the White House released a long-form birth certificate for Obama in 2011.

Arpaio laid out several claims on Thursday that he said prove Obama’s birth certificate is fake.

“This investigation was never about where president Obama was born,” Arpaio said, according to reports. “We were going to investigate a government possible forged document.”

Arpaio claimed that his team had “concluded” that the birth certificate was forged.

Trump conceded earlier this year that he now believes the president was born in the U.S.