(BOSTON) -- Boston police and federal authorities are questioning whether an explosion ever took place on the Northeastern University campus Tuesday evening, law enforcement sources told ABC News.
Police and school officials said Tuesday that a package had detonated at the university, resulting in a school staff member sustaining a minor hand injury.
Boston EMS had responded to reports of an explosion at the university, with the 45-year-old victim transported to an area hospital with non-life-threatening injuries, according to police and officials.
The Northeastern University staff member who allegedly sustained injuries in what authorities called a "package detonation" had opened a hard-backed, Pelican-type case, law enforcement sources told ABC News.
There’s no apparent damage to the case and investigators have found no evidence of an explosion occurring, the sources said. Instead, authorities are looking at whether the entire thing was a hoax.
The alleged package was sent to Holmes Hall on Leon Street, where police responded at 7:18 p.m., authorities said. Boston Police Superintendent Felipe Colon said there was a second similar package that was rendered safe by the bomb squad.
Law enforcement's preliminary assessment is that the reported minor explosion on campus was not random, two sources briefed told ABC News.
Authorities also found what the sources described as an anonymous note railing against virtual reality, among other things.
There is no intelligence indicating a further threat, according to the FBI’s Boston office.
A manager at Northeastern's virtual reality lab, the sources said, is apparently the 45-year-old male staff member who was hurt. The injuries are reportedly minor abrasions to both forearms.
In a statement to Boston ABC News station WCVB, Northeastern University said a package delivered to Holmes Hall "detonated when a staff member opened it."
A second suspicious package was cleared and did not contain an explosive, according to the two sources. There have been a number of reports of suspicious packages that police have checked, and they've searched buildings and mail rooms at Northeastern and nearby colleges for similar-looking packages, the sources said.
Boston Police Commissioner Michael Cox said a number of campus buildings were evacuated. He urged citizens to come forward if they see something out of the ordinary.
"We're trying to gather facts now," Colon added.
"The building has been evacuated and a notification was sent to the Boston campus at 7:55 p.m. urging people to avoid the area. We will update members of the Northeastern community when more information is available," the university added in its statement.
Police for Northeastern University urged people to avoid areas around the school's Holmes Hall as they conduct an investigation into the incident.
Nearby colleges and universities in and around Boston were advised to be on watch for similar-looking Pelican-type cases.
Sources said the case appears to have contained no explosive material. Instead, it was believed to have had somehow been pressurized and, when opened, rapidly depressurized, causing the supposed detonation.
The Boston Police Department's bomb squad, Boston EMS and the Boston Fire Department were all on the scene investigating the incident, officials said. The Bureau of Alcohol, Tobacco, Firearms and Explosives is assisting with the investigation, according to a spokesperson.
Northeastern is a private research university located in Boston.
ABC News' Josh Margolin, Arielle Mitropoulos and Jack Date contributed to this report.