Austin, Texas ? The FBI sent a team of experts on weapons of mass destruction Saturday to collect samples of a powder found in a University of Texas student dormitory that were preliminarily identified as the deadly poison ricin.

A student discovered the powder Thursday afternoon in a roll of quarters she was using to operate washing machines in Moore-Hill Hall. She notified dormitory officials, who brought in university police and local health authorities.

After an initial positive test, other tests conducted by the Austin-Travis County Health and Human Services Department and state authorities gave inconclusive or negative results, FBI spokesman Richard Kolko said from Washington on Saturday. The FBI’s Joint Terrorism Task Force is investigating and conducting further tests.

The dormitory was temporarily closed for decontamination, and the 400 students living in Moore-Hill Hall were notified of the results at a late-night briefing at a nearby dorm. Other than the laundry room and a portion of the second floor, Moore-Hill was reopened to students.

Special Agent Rene Salinas, of the FBI’s San Antonio office, said the agency believed the incident “is not terrorist connected.” But he said a team of WMD experts from FBI headquarters in Quantico, Va., had flown to Austin to collect samples of the powder for further testing. Other federal agents “are trying to determine the exact origin of this material,” Salinas said.