A 30-year-old man who coached the cross country team at a Baltimore County private school and worked full time for the Girl Scouts has been charged with soliciting sex on the Internet from a 13-year-old female pupil at the school, police said yesterday.

Adam Theodore Rubin of Arnold, a coach and former teacher at Beth Tfiloh Community School who also worked as an outdoor program coordinator for the Baltimore office of the Girl Scouts of America, was charged with several sexual offenses, including engaging in child pornography on a computer. He posted a $10,000 bond and was released from the Garrison precinct yesterday.

He is accused of arranging to meet the girl, whom he once taught at Beth Tfiloh, at Greenspring Shopping Center on Wednesday night. Instead, he was confronted by county vice detectives who had been following him all day and had posed as the girl in conversations on the Internet.

Rubin has been suspended from his job with the Girl Scouts and has been fired from his position as a coach for the Pikesville school, which also has a campus in Glyndon.

A woman who answered the phone at Rubin's home in Arnold yesterday said they had no comment about the allegations.

A spokeswoman for Beth Tfiloh Community School, Joan Feldman, said, "We are concerned for our students."

In a prepared statement, school officials said, "Beth Tfiloh has taken an aggressive and proactive stance in this matter to avoid repeat offenses. Beth Tfiloh continues to provide support for teachers, parents and students who have been affected by their involvement."

Girl Scout officials declined to say how long Rubin has worked for the organization. However, Cassandra Champion, a spokeswoman, said he passed a comprehensive background check before being hired. She said he would remain suspended from his job until the investigation was completed.

"Our primary concern is the health and safety of the girls we serve," Champion said. "Authorities have assured us that none of our members have been involved in any way."

Several female Beth Tfiloh pupils, ages 12 and 13, told a staff member at the school last week that they had been exchanging e-mails with Rubin and that his messages had become sexual in nature, police said.

The school contacted Baltimore County police who subpoenaed the coach's America Online account information, according to charging documents.

Police interviewed one of the girls who had been corresponding with Rubin since he left Beth Tfiloh as a teacher about a year ago, the court records show. The girl told police that their conversations had turned more sexual at the beginning of this school year, police said.

With the permission of the girl's parents, detectives began Monday having conversations with Rubin on the Internet using the girl's account, according to the charging documents. The e-mail messages quickly turned sexual, with Rubin explicitly describing how he wanted to sexually interact with the girl, police said. The next night, he expressed concern about what would happen to him if he was caught having sex with a minor, according to the charging documents.

A meeting to consummate the online relationship was scheduled, the documents said. Rubin told the girl to wear something "comfy" but that he liked "tight miniskirts" and "midriff tops," the documents said.

Police arrested Rubin in a sport utility vehicle near the atrium of the Pikesville shopping center. According to the charging documents, Rubin told police he had received as many as 30 pictures on the Internet from underage girls either nude or in a state of arousal and that he thought he had a "problem -- an addiction to the Internet, talking to young girls on it."