Three teenagers accused of forcing girls as young as 12 into prostitution have reached plea agreements and been sentenced to a juvenile detention center.

The boys — two are 17 and one is 16 — will be released no later than their 19th birthdays, according to the plea agreement.

They each pleaded guilty Thursday to one count of compelling prostitution. In exchange, prosecutors dropped other charges, including human trafficking. Charges against others allegedly involved in the ring are pending in adult court.

Police said they discovered the ring in August after a woman was caught offering men sex with a 14-year-old girl for $50. The teenagers were arrested in January after they had taken the girl to a convenience store to have sex with the owner, a regular customer of the ring, police said.

The teens, suspected members of the Varrio Central gang, were accused of befriending runaways and other girls with unstable homes and taking them to regular customers or finding new ones by trolling apartment complexes.

If the girls refused to have sex for money, the gang members beat and sexually assaulted them and threatened their families, police said.

One girl's mother said she was disappointed the teens would not spend more time in state custody. Her daughter is in counseling and is afraid of them, she told the Fort Worth Star-Telegram.

"These girls have to live with what happened for the rest of their lives," said the mother, who was not named to conceal the identity of her daughter. "These boys aren't going to serve much time. I don't think that after a year and half, they'll be ready to get back into society."