Story Published: Nov 18, 2008 at 9:52 AM EST

Story Updated: Nov 18, 2008 at 11:41 AM EST

SACRAMENTO, Calif.- A former opponent of Barack Obama's has come back to haunt him over questions regarding Obama's citizenship.

According to a press release from the American Independent Party, former presidential candidate Alan Keyes and other members of the party have filed suit in California Superior Court in Sacramento to stop the state from giving its electoral votes to President-elect Barack Obama until documentary evidence is provided to prove Obama is indeed a natural born citizen of the United States.

Some conservatives have questioned Obama's citizenship in recent months. Obama says he was born in Hawaii in 1961.

Keyes also ran against Obama as a Republican for the U.S. Senate seat in Illinois in 2004. Obama won that election to serve his first and only term in the U.S. Senate.