(Newsroom America) -- Contentious Arizona Sheriff Joe Arpaio said Tuesday an investigation has found that President Barack Obama's birth certificate is "definitely fraudulent," as he called on Congress to act.
The Maricopa County sheriff made his accusation at a press conference in Phoenix, which he said was the result of a months-long investigation by his Cold Case Posse.
The posse's lead investigator, Michael Zullo, said the investigation's findings substantiate Arpaio's earlier claims that the long-form birth certificate Obama released to the public in April 2011 was forged.
"Although I am having a difficult time deciding who to forward this information to given the fact that the obvious choices report directly to the president, I cannot stand by and hold on to information that threatens to weaken national security," Arpaio said.
Zullo said numeric codes on the birth certificate indicate that those parts weren't initially filled out, but those sections asking for the race of Obama's father - which says "African" - and his field of work or study were completed.
Zullo said initially investigators weren't sure what the numeric codes meant, but added they were explained by a 95-year-old former state worker who signed Obama's birth certificate.
He added that an author who published a book about Obama's birth certificate and was assisting the investigative team allowed them to listen in on an interview he held with the worker, identified in a Washington Times report as Verna K.L. Lee.
The investigative team, in its report, said that, according to Lee, Obama's birth number should have been lower than a pair of twins born after him on the same day, yet his number was higher.
"This proves that Obama could not have been born at the Kapiolani Medical Center as reported. The numbering on his certificate is more consistent with a birth certificate that had been turned in from one of the outlying areas," the report said.
The Obama campaign had no comment on Arpaio's announcement.
So-called "birthers" - those who doubt Obama was born in the U.S., which is a constitutional requirement to be president - say he was actually born in Kenya.
State officials have repeatedly confirmed that Obama was born in Hawaii, and they did so once more Tuesday.
"President Obama was born in Honolulu and his birth certificate is valid," Joshua A. Wisch, a special assistant to Hawaii's attorney general, said in a statement to The Associated Press. "Regarding the latest allegations from a sheriff in Arizona, they are untrue, misinformed, and misconstrue Hawaii law."
Earlier reports, however, have suggested that Obama was born in Kenya, such as a 1991 pamphlet put out by his then-literary agent who said he "was born in Kenya and raised in Indonesia and Hawaii."
While it's unclear why the agent said his client was born in Africa, some have suggested he may have embellished Obama's background to make him sound more interesting.
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