CHICAGO (CBS)–The non-profit Heartland Alliance has rejected claims immigrant children were mistreated under their care.

Two Brazilian boys were reunited with their mothers weeks ago in Chicago, but not all have been as lucky.

The boys told reporters they saw a child “injected with something that made him fall asleep,” CBS 2’s Vince Gerasole reports.

Another child was given a cast for a broken arm by non-medical personnel, and a third was dragged off a playground–all while in the care of Chicago’s Heartland Alliance.

“We were horrified to read those allegations–they came as a huge surprise to us,” said  Evelyn Diaz, president of Heartland Alliance.

In an audio briefing, Heartland Alliance said it voluntarily reported the claims to the Illinois Department of Children and Family Services, and also conducted an independent investigation.

The results of that investigation found nothing to support the allegations, Heartland Alliance said.

“Because of the regulations (requiring the facilities to be under surveillance) there are cameras in all common areas and that means there are cameras in the classrooms,” said Linda Coberly of Heartland Alliance.

Chicago Alderman Joe Moore (49) said the internal investigations weren’t going far enough.

“Never before have any complaints of that nature been brought against Heartland,” Moore said.

Several other outside investigations are ongoing.