Knife deeds are being investigated as terrorist offenses.
The perpetrator indiscriminately went on an attack in Forbury Gardens where he killed three people and injured three others.
The 25-year-old, who is from Libya, was arrested shortly afterwards. The man, according to the public service company BBC's sources, is known by the British security service but has previously not been deemed to pose a serious threat or an imminent risk.
The city of Reading is approximately 6.5 miles west of London.