Updated

The FBI determined Wednesday there was no threat to students on the Newark campus of Rutgers University after a student was arrested and his dorm was searched for potentially hazardous substances following a tip from authorities in South Dakota.

Helen Paxton, a school spokeswoman, said the FBI's investigation of the dorm had concluded by late Wednesday afternoon, and students were allowed to re-enter the building -- which had been evacuated twice in two days. Earlier in the day, students had gathered behind police tape in a large cordoned-off area around the dorm building, trading rumors about what was going on.

Police arrested sophomore Elan Haba of North Caldwell on Tuesday night on various charges and evacuated his dorm for about two hours after potentially dangerous materials were found and removed. The 19-year-old was arrested following a tip from authorities at The University of South Dakota, where a former student with an alleged connection to Haba had been found with suspicious materials.

Haba was released on a summons. University officials did not know if he had retained a lawyer. A phone message left at a number listed under the family's name was not returned by Wednesday evening.

Local law enforcement officials evacuated Haba's dorm and surrounding buildings Tuesday night for about two hours and removed materials from Haba's room. Paxton said the FBI conducted a subsequent investigation on Wednesday after informing Rutgers officials that a potentially hazardous substance may not have been detected in the first sweep.

Haba's dorm building, called University Square, was briefly evacuated again Wednesday while the FBI conducted its investigation. Rutgers officials said Wednesday the investigation was ongoing and they would not be revealing what kind of materials were found, other than to say some were available for legal purchase and by themselves could be considered harmless but others were potentially harmful. Rutgers officials said the investigation was not drug related.

Paxton said Haba faces multiple charges including theft, possession of fireworks and possession of a prohibited weapon. School officials said Wednesday the theft charge was related to some university property discovered in his room, but declined to say what it was. The prohibited weapon was a knife owned by Haba, authorities said.

Haba's arrest came after authorities in South Dakota found suspicious materials in a dorm room on campus Tuesday night. That came after the parents of an out-of-state student who had left the University of South Dakota after the winter semester asked officials to check on the student's belongings, according to a report in the Argus Leader.

USD Spokesman Phil Carter told The Associated Press on Wednesday that an item located in a dorm at the school's Coyote Village was linked to an address located at Rutgers University. He referred all further questions to the Division of Criminal Investigation, which did not return a phone call seeking comment.

Teddi Gertsma, the Clay County State's Attorney in South Dakota, said no charges had been brought against the former USD student. Gertsma said she was waiting for more information from the Division of Criminal Investigation before deciding if charges would be filed.

Kemel Dawkins, the executive vice chancellor for administration at Rutgers-Newark said Wednesday that Haba and the former student in South Dakota were believed to have grown up together in the same area of New Jersey.