WORCESTER, Mass. —  A doctor at UMass Memorial Medical Center has been charged with soliciting sex from an undercover Worcester, Mass., police officer who was posing as a prostitute.

But Dr. Peter Rice said he is not guilty and was only "gathering information" when he was arrested Saturday. He told the Telegram & Gazette that he is a specialist in infectious diseases and researches sexually transmitted diseases.

Rice offered the undercover female officer $40 for sex, police said. His arrest came as part a two-day prostitution sweep in the Main South section of the city.

The 65-year-old Rice is a professor at the University of Massachusetts Medical School and has published dozens of articles about infectious diseases.

He's scheduled for arraignment Wednesday in Central District Court.