A residential social care worker has been arrested on suspicion of child abduction, abuse of trust and drugs offences in County Londonderry.
The 25-year-old man has been released on bail pending police enquiries.
It is understood he was an agency worker in the mid-Ulster area and that several teenagers were in his care.
The BBC understands this has now become a major safeguarding issue for a number of Northern Ireland’s health authorities.
To protect the identity of the children at the centre of the allegations, the BBC is not reporting which health trust is handling the case.
In a statement, the health authority confirmed that as a result of information they received, an agency worker’s contract had been terminated.
The statement added that police had been alerted and the trust was aware of an ongoing investigation.