KSTP reports a rural Pine County man has been arrested in the mysterious case of envelopes sent to the Pine County courthouse on Nov. 19.
The six envelopes contained a white powder, later determined to contain a harmful bacteria. Authorities shut down the courthouse and evacuated 200 people.
Police arrested the 45-year-old suspect late Thursday, according to Northland's NewsCenter. The Pine County Sheriff's Office said the man had already been under investigation by the FBI for making and planting devices meant to look like explosives.
According to FOX 9, investigative agencies including the St. Paul Police Department Weapons of Mass Destruction Unit, the Minnesota National Guard 55th Civil Support Team and Pine County sheriff's deputies executed a search warrant at the suspect's home.
The FBI said the powder revealed a sophisticated refining technique which could be used to make deadly bacterial weapons.
The suspect is in custody at the Pine County Jai awaiting charges.