From BND:

Female Scout leader accused of sex with young boy

St. Clair County sheriff's detectives are investigating a female
Boy Scout leader who is accused of molesting a teenage boy on
Sunday.

"The boy's parents called us when they came home, and their
child was having sexual intercourse with an older female in his
bedroom," Sheriff's Capt. Steve Johnson said. "They blocked the
female from leaving until deputies arrived.

Deputies arrested the woman, who is being held in the county
jail. She has not been charged.

Investigators are checking when the relationship began because it is known that the female is involved with Boy Scout Troop 35 in O'Fallon, and the boy also is involved with the troop.

The woman was not identified because charges are pending. The age of the boy, who is younger than 18, could not be immediately confirmed.

"Investigators are working on the case and, depending on how the investigation goes, charges are expected tomorrow or Wednesday," Johnson said.

Boy Scouts of America leaders issued a statement Monday and said that they are cooperating with authorities.

"We were shocked and deeply saddened to learn about the allegations against this council volunteer," said Alicia M. Lifrak, the scout executive for the Lewis and Clark Council of the Boy Scouts of America.

"Upon learning of these allegations, we immediately revoked her membership. She will never be allowed to participate in Scouting again," Lifrak said.

"The BSA seeks to prevent child abuse through a comprehensive program of education, chartered organization leader selection procedures, criminal and other background checks, barriers to abuse, prompt reporting and swift action," she added.