Northampton County District Attorney John Morganelli said Wednesday that investigators determined the boys ingested the hallucinogenic drug.
Morganelli says the boys, ages 7 and 10, were foaming at the mouth and hallucinating after arriving at Bangor Elementary School on Sept. 24. They were hospitalized and released the following day.
Morganelli says investigators couldn't get fingerprints from the bottle to trace it.
He says the boys' mother and her live-in boyfriend tested negative for drugs and there were no issues inside the home.