Durham, N.C. — The Durham Police Department was locked down briefly Wednesday afternoon when an envelope containing a suspicious white powder was delivered to someone in the department, authorities said.

The powder was discovered at about 12:15 p.m., and all entrances and exits to the headquarters building were blocked, Durham Fire Department Capt. Chris Iannuzzi said.

The fire department's hazmat team and the police department's Biological Chemical Emergency Response Team suited up in protective gear and set up a decontamination tent to investigate the incident.

The building was reopened about 90 minutes later when authorities determined the suspicious material was thyme seeds.