BIRMINGHAM, England, Feb. 25 (UPI) -- Former Guantanamo detainee Moazzam Begg was arrested with three other individuals Tuesday in England for Syria-related terrorism offenses, authorities said.
Begg, 45, was arrested in Birmingham and is suspected of attending a terrorist training camp and facilitating terrorism overseas, the Guardian reported.
The United States had held him in Guantanamo Bay, but charges were not levied and he was released in 2005.
Two other men and a woman have also been arrested on suspicion of facilitating terrorism overseas.
The four suspects are being held at a police station and their homes are being searched, officers said.
"We would take this opportunity to remind you of the requirement to report responsibly, that this is an arrest, not a charge, and that our naming does not imply any guilt," police said.
Begg is a member of Cageprisoners, which campaigns for people who are unfairly targeted by the war on terror.
He traveled to Syria in 2012, and said he was investigating the West's complicity in torture occurring in the country.
"I am certain that the only reason I am being continually harassed -- something that began long before any visit to Syria -- is because Cageprisoners and I are at the forefront of investigations and assertions based on hard evidence," he wrote at the time.