(Portland, Oregon) The state’s attorney general agreed Wednesday to investigate claims made by the mayor of Portland that he lied to cover up a sexual relationship with an 18-year-old boy.

Adams, who is 45, said the teen was 17 when they met in 2005, and that the relationship did not turn sexual until the boy turned 18. He said he lied because he was afraid voters wouldn’t believe that his young lover had turned 18 before they started having sex.

Adams became mayor on New Year’s Day, making Portland the largest U.S. city with an openly gay mayor.

Oregon Attorney General John Kroger agreed to an investigation after Multnomah County District Attorney Michael Schrunk and Portland police Chief Rosie Sizer asked Kroger to look into the affair.

Also on Wednesday, three Portland newspapers and the city police union called for Adams to resign.

Adams had said he would resign if staying was not in the city’s best interest.

The publisher and editorial board of Just Out, a newspaper serves the gay and lesbian community, said in a statement that “Adams has failed to show the principled character that this publication feels is a basic requirement for an elected official.”

“Right now one of the big things we in government need is credibility with the public,” Schrunk told The Oregonian, another newspaper calling for Adams to resign. The police chief said it would be inappropriate for her department to investigate the mayor.

City commissioner Nick Fish said the commissioners met Wednesday and joined the request for an investigation by the attorney general. They decided to withhold comment until that investigation was completed.

“This is clearly a distraction, but people need to know we are getting work done,” Fish said.

Unless Adams bows to pressure and resigns or there is evidence of a crime, he will remain in office for the first half of 2009 because state law bars any mayoral recall until after six months.