SEATTLE — A 43-year-old Agnew woman appeared Tuesday in U.S. District Court facing a felony count of sending threatening mail to a Sequim police officer.

One of the letters she allegedly sent in April 2003 contained a powder that spurred a bioterrorism scare and shut down a postal distribution center in Tacoma.

Janet Ann Miller was taken into custody Monday by investigators from the U.S. Postal Inspection Service who were armed with arrest and search warrants at her residence in the Agnew area west of Sequim.

The U.S. Attorney’s Office in Seattle said investigators were acting on information from Miller’s psychiatrist.

A criminal complaint unsealed Tuesday said the threatening letters she’s accused of sending have been under investigation for more than a year.

Miller, formerly a registered nurse, is suspected of mailing a threatening letter in April 2003 addressed to the Sequim Police Department which contained a white powdery substance.

Postal center evacuated

Employees at the U.S. Postal Service sorting facility in Tacoma discovered the powder next to the letter on a sorting table and immediately notified authorities.

The facility — which sorts mail to and from North Olympic Peninsula post offices — was evacuated and closed for several hours, and some employees were sent to the hospital for precautionary decontamination and treatment.

Biologists later determined that the substance was not a biotoxin.

If convicted of mailing threatening communications, Miller could face a maximum five years in prison, followed by three years of supervised release and as much as $250,000 in fines, the U.S. Attorney’s Office said.

Miller remains at the federal detention center in SeaTac, and is scheduled for a detention hearing Aug. 2 and a preliminary hearing Aug. 11.