D.C. Police say a dorm on the campus of Georgetown University is safe after someone reported finding a powdery substance early Tuesday morning.
Authorities were called to McCarthy Hall in the 3700 block of O Street NW early Tuesday morning for the possibility of ricin in the building.
A school spokeswoman says a test for "biological agents in the area were negative."
Authorities will conduct additional tests on the material. School officials say a subject is being interviewed in connection with the incident.
Stay with NBCWashington on-air and online for more on this developing story.
