ST. JOSEPH, Mo. -- Buchanan County authorities filed charges Friday against two middle school girls after nine students went to a hospital after taking methadone at school.

Authorities charged the girls with felony delivery of a controlled substance.

Thursday, prosecutors charged a 16-year-old boy with delivery of a controlled substance. Police said he gave one of the girls the methadone and the girls gave them to the other students. It wasn’t immediately clear whether investigators believed the second girl also handed out the pills.

All three were in juvenile detention. The boy was taken into custody Wednesday night.

Methadone is a pain reliever used to treat people battling drug addiction.

Nine girls, according to a letter the St. Joseph School District sent to parents, were taken to a hospital after ingesting the methadone pills at Spring Garden Middle School.

The St. Joseph News-Press provided KCTV5.com with a copy of the letter.

A lawyer in the juvenile office said Missouri law would allow the three to be charged as adults.

Police, Parent React

"We have heard about methadone being misused, but this is the first time we have seen it in schools like this where it's been students who've been affected by it," said Sgt. Kevin Castle of the St. Joseph, Mo., Police Department.

A St. Joseph mother was "terrified" by the incident.

"I have two children getting ready to go to middle school and to know that that is in our city and is going around our schools, it just absolutely terrifies me," Shablix Jones said. "My heart is just racing knowing that is here and it's going around. It can kill the children."

All of the students were expected to be OK, but an emergency room physician said methadone was an effective drug when used properly but an overdose could be deadly.

Dr. Pamela Ramsey said, "If they took it, you don't catch them, the next thing is you may be walking in trying to wake up a child that doesn't wake up, every parent's nightmare."