A judge was convicted Rep. Vito Fossella of drunken driving and will later decide if he should serve time in jail.

The New York Republican was arrested May 1 in the suburbs outside Washington, leading to revelations he had fathered a child from an extramarital affair. After the scandal, he decided not to seek re-election.

Fossella's attorney Barry Pollack said they are, "very disappointed in the judge's ruling."

"[Fossella] admitted that he made a mistake," Pollack said. "But, what remains in dispute was whether he was at the level that the Commonwealth alleges."

Police say his blood-alcohol level was 0.17 percent, and under state law anyone convicted of having a BAC above 0.15 must serve a mandatory five-day jail term.

Alexandria, Va., General District Court Judge Becky Moore found Fossella guilty, and scheduled a Dec. 8 hearing to decide if prosecutors had met the legal requirement for high blood alcohol content.

In addition to the DUI conviction, Traffic Court Judge Becky Moore found Fossella guilty of running a red light and fined him $100.

FOX News' Chad Pergram and the Associated Press contributed to this report.