FBI agents spent the morning and part of the afternoon searching a house and barn at 30 Hudson Street in Manchester as part of an ongoing investigation.
Few details are available other than that the FBI was acting on a search warrant.
Local and state police are also at the scene and said that they are always called in whenever another agency is working.
It's not clear who is at the center of the investigation.
NBC Connecticut knocked on the door and it appeared people were inside, but no one answered.
The family who owns the house now bought the property in 2008 from an estate, according to the Manchester tax office, and online tax information says the property includes a barn with a loft and a shed.
According to neighbors, a large family has lived in the house for a few years. While they report seeing several cars and people come and go from the house, they have never noticed any cause for alarm.
The FBI had left the scene by mid-day.