A 45-year old man from Wellingborough has been arrested on suspicion of offences relating to the distribution of terrorist documents.
The man was detained at 6.30am on Tuesday by plain clothes officers from the West Midlands Counter Terrorism Unit, supported by Northamptonshire Police.
He was later released on bail until March, pending further enquiries.
Officers made a search of the suspect’s home address, which has now been completed.
Some items were seized for forensic analysis.
One eyewitness said a number of unmarked vehicles arrived at the house at about 6.30am and officers remained at the property until about 6pm.
Superintendent Andy Cox, from the County Operational Command Unit, said: “The suspected documents are of an ideological nature – not instructional manuals such as bomb making.
“We want to reassure the community living in the surrounding area that the arrest was pre-planned, intelligence-led and not made as a result to any immediate threat to public safety.”
Although part of West Midlands Police, West Midlands CTU is a regional unit – one of five across the country which form the counter terrorism policing network.
Most of its work is based within the West Midlands Police area but they can also be assigned responsibility for investigating cases anywhere in the country.