DES MOINES — Authorities locked down the Iowa Statehouse on Tuesday afternoon and wouldn’t allow anyone to leave the building after a legislator opened an envelope that contained white powder and a threatening letter.

House Speaker Kraig Paulsen said initial tests indicated the powder was not hazardous, but that crews needed to perform more tests to confirm that assessment.

The letter was opened by Rep. Ako Abdul-Samad, D-Des Moines, on the House floor. He was taken to a vestibule room off the House chamber while postal inspectors and a Des Moines Fire Department hazardous material team were summoned to examine the substance.

Paulsen, a Republican, declined to describe the letter or describe the white powder. He suspended the House’s business while the inspection was under way.