Updated at 2:54 pm
The 40 evacuated court employees have left the police station, where they congregated after the powder was discovered.
Court proceedings are canceled for the afternoon.
The HAZMAT team says the court is safe and secure, though it'll take another 4 to 6 weeks of testing to figure out exactly what kind of powder the envelope contained.
Meanwhile, four of the employees exposed to the mystery powder are being quarantined and examined in the hospital. They're not exhibiting any symptoms or illness, says Warren Police Commissioner Jere Green.
He says either the city police or the FBI will take the investigation from here.
The city of Warren evacuated the 37th District Court this morning because of a suspicious letter containing white powder.
According to Christina Hall from the Detroit Free Press, Warren Mayor Jim Fouts said no one was hurt or sickened.
About 40 employees were at the neighboring police station awaiting the all-clear from the fire department to return to the court, 8300 Common Road.
Fouts said a letter was mailed from Chrysler to a third party and was delivered to the court by mistake. The clerk re-mailed the letter to the third party. On Friday, the letter came back to the court as undeliverable, Fouts said.
He said the clerk opened the letter this morning and the powder came out. Police, fire and Hazmat were called.
“The intended target was not the district court,” Fouts said, adding that he did not know to whom the letter was addressed or the type of letter it is.
Fouts said the substance did not appear to be a potentially dangerous one and that he anticipates the court will reopen today.
- Chris Zollars, Michigan Radio Newsroom