Maricopa County Sheriff Joe Arpaio questioned the validity of President Obama's birth certificate at press conference Thursday. The sheriff's critics blasted his presentation, which took place during an election year and amid a federal investigation into civil rights allegations at Arpaio's department. From Phoenix, Devin Browne reports.

DEVIN BROWNE: The sheriff’s volunteer Cold Case Posse headed up the investigation. This is after 250 members of the Surprise Tea Party petitioned the sheriff to look into the validity of the president’s birth certificate. Sheriff Arpaio announced he suspects forgery and fraud.

JOE ARPAIO: I’m considering asking the Hawaii authorities to look into this, but as my investigators and I feel – will they really do it?

BROWNE: In fact, Hawaiian authorities have been asked to look into this for years. Obama responded last April by posting his birth certificate on the White House website, which has been recognized as an official document from the Hawaii Department of Health. Arpaio will face two challengers to his seat as sheriff this November. One of them – Paul Penzone – criticizes the sheriff for making time to investigate the president’s documents, when his office ignored other investigations, like the sex crimes in El Mirage several years ago.

PAUL PENZONE: The sheriff’s statement was an insult to law enforcement, and a slap in the face to the victims in this community who his office failed to serve when they were victimized.

BROWNE: Scottsdale Police Lt. Mike Stauffer is also running for Maricopa County Sheriff this year. He noted that Thursday’s press conference coincided with this week’s court appearance of Joel Fox -- the former Sheriff’s captain who is accused of money laundering during the sheriff’s 2008 campaign, and may now be under a federal investigation of his own.