Anthony Ross swore he never had sex with the 10th-grade girl.

The onetime H.D. Woodson High School football coach swore he never wrote beseeching letters to her. He swore he never entered the 15-year-old's home. And he swore it was some other man talking dirty to her on a recording that the girl's mother made--even though caller ID showed that the call originated from his Woodson office.

He swore the relationship was strictly teacher-student.

D.C. Superior Court Judge William M. Jackson decided that Ross was lying.

Jackson said there was "simply no doubt" as he convicted Ross, 31, of child sexual abuse yesterday. He declared him a danger to the community and ordered him to jail to await sentencing.

Ross is the fourth D.C. public school employee or volunteer convicted this year of child sex abuse charges. The other cases involved sex with young teenagers at Ronald H. Brown Middle School, Shaw Junior High School and Lincoln Junior High School.

"Your honor, can I say something?" Ross asked after Jackson convicted him of the misdemeanor charge, punishable by as many as 180 days in jail. "Your honor, again I stand here, and I'm telling you I'm innocent."

Jackson had just finished reciting, witness by witness, the formidable evidence against Ross. When Ross sat down, the judge had a few more choice words.

"I specifically did not believe you, and I do not believe you," the judge told the defendant as Ross's wife watched from the gallery. "I believe you engaged in the conduct. I believe it was reprehensible conduct."

The poised teenager who testified against Ross said their affair lasted a short time. She welcomed the tryst, she said, and spoke to authorities only when her family insisted she do so. Because she was not yet 16, it was against the law for Ross to have sex with her.

She decribed the day in March when Ross went to her house.

"We talked. We hugged. We kissed. We laid down together," she said. "He was kissing me. I was kissing him. I guess we both knew the sex was coming next. . . . We had sex for a short period of time."

The girl, who has transferred to another school, testified that she and Ross also hugged and kissed in his Woodson office, where he was an attendance officer and a defensive coach for the football team. Ross departed for a private school after the allegations surfaced.

One night, the girl said, the pair secretly embraced in the bathroom of the sixth-floor teachers lounge as her mother attended a PTA meeting on another floor.

"I find her testimony credible and compelling. I find that she was quite truthful," Jackson said of the girl.

The judge also said the girl's godfather was believable when he described confronting Ross--a conversation that Ross said never happened.

"I don't doubt for one moment that there are folks who don't believe--or don't want to believe--that Mr. Ross did this," Jackson said. "There is literally no doubt in the court's mind that the defendant is guilty of misdemeanor sexual abuse."