Local police, along with federal and state authorities, spent several hours Monday at an undisclosed Tokeneke residence investigating a letter containing a suspicious, white powder.
The investigation has been turned over to the FBI's New Haven office.
The powder was removed from the home about 7:30 p.m. by the State Police Emergency Services Unit, according to Darien police. Preliminary tests will be conducted on the substance before it is turned over to the Federal Bureau of Investigation.
A definitive identification of the substance may take up to five days, police said.
Residents of the area were interviewed by the Darien Police Detective Division and the FBI, with officers on the scene canvassing numerous neighboring streets, including mailboxes looking for evidence, police said.
The Darien police were the first to arrive on the scene, after the Tokeneke constable called them shortly after 2:30 p.m. and said a resident had shown him a threatening letter containing the suspicious, white powder.
The envelope was delivered to a home at the private association, Darien Police Sgt. Jeremiah Marron said Monday. He declined to specify the street location or number of the home.
Police and investigators have been unable to determine why the letter was delivered to the home in question, Marron said.
"Depending on what the substance turns out to be will determine who has jurisdiction," Marron said. "If it is a harmful substance, I imagine the FBI will carry the jurisdiction."