DURHAM, N.C. (WNCN) — An investigation is underway after a letter containing a “threatening message” was sent to Durham Chief of Police Patrice Andrews on Tuesday, police said.

According to the Durham Police Department, the suspicious letter addressed to the police chief was opened in her office suite at around 7:15 a.m.

“The letter contained a threatening message and a powdery substance,” the police department said in a Tuesday news release.

The Durham Fire Department responded and tested the substance, but it did not test positive for any known harmful substance, police said.

Durham police chief claims Charlie Kirk ‘disguised himself as a Christian’ in social media post

After collecting the substance, officers are actively investigating the source of the letter.

“At this time, there is no known threat to the safety of staff or the public,” the news release stated.

This is nearly two weeks after a social media post on Andrews’ private Facebook page spurred calls for city leadership to remove her from her high-ranking position.

Andrews, who’s served as police chief since November 2021, spoke candidly about her views of conservative activist Charlie Kirk, who was assassinated on a Utah college campus in front of thousands of students earlier this month.

This is a developing story. Check later for updates.