One of three Bethesda high school students charged with beating and sexually assaulting a woman from an escort service was sentenced yesterday to a juvenile correctional facility for an unspecified term, a prosecutor said.

Montgomery County Circuit Court Judge Marielsa A. Bernard ordered Ryan H. Baird, who turned 15 yesterday, to the custody of the juvenile system until he is deemed fit for release or until he reaches his 21st birthday, Assistant State's Attorney Jeffrey Wennar said.

Baird and two other boys, ages 15 and 19, lured the woman to one of their homes Nov. 8 by offering her a job in an adult video, court documents say.

When she arrived, the boys attacked her, hitting her twice with a baseball bat, forcing her to disrobe at knifepoint and sexually assaulting her with the bat handle and a large ink marker, the documents say.

Baird grabbed her and covered her mouth with a damp cloth that emitted a medicinal odor when she arrived at the home, the documents say.

Baird was charged by a grand jury as an adult after the Nov. 8 attack, but his attorney, assistant public defender Penny Kahn, moved Feb. 4 to return him to the Juvenile Division of the Family Court. After reviewing psychological reports and other evaluations, prosecutors did not oppose the motion.

On Feb. 13 in a closed hearing, Baird pleaded guilty as a juvenile to first-degree sexual assault and other crimes, Wennar said.