The man arrested at the scene yesterday is Khairi Saadallah, a 25-year-old refugee from Libya, The Telegraph can reveal.
Mr Saadallah was detained by police in Forbury Gardens on Saturday evening. Witnesses claimed he approached a group of middle aged men who had been sat drinking in the park and suddenly began stabbing at them.
Three men died in the attack and at least three others are in a critical condition in hospital.
It is understood Mr Saadallah came to Britain several years ago as a refugee following the civil war in Libya.
Mental health is being considered a major factor in the incident, security source said.
Armed counter terrorism police raided his flat in nearby Basingstoke Road late on Saturday night and removed a number of items including a large circular saw.
Neighbours at the flat block where he lived in Whitley, just under two miles from the scene of the mass stabbing, believed he had been recently released from prison. Three people were killed and a further three victims seriously injured, making it the deadliest terrorist incident to strike Britain since the June 2017 London Bridge attack. A local woman, who did not want to be named, told The Independent the flat where the suspect lived was council-owned and used as temporary accommodation, including for people recently released from prison. Possibly for this incident. Or this. Or maybe this. He seems to have a problem with authority figures.
Dan, a 26-year-old local, said he was drinking wine in the park with two friends when he noticed a commotion about 20 metres away. He described how he and his friends had chosen a spot to sit and enjoy the sunshine when he saw a man approach a group "just in a circle chatting".
The man drew his attention because he appeared to be racing around the group "tapping them on the head". Reflecting on the disturbing moment he realised it was an attack, Dan said: "I thought they were playing duck duck goose and thought someone had been sick, we realised it was blood spraying out."
He and his two friends sprang up and began running as they saw the attacker move toward another group in what he thought was a random attack. Dan said he saw the man take a blow to a woman's neck- but couldn't be sure if he was using a knife as he and his friends never got a close look at the weapon. The woman "dropped like a weight," Dan said. Four people were on the ground and "immobile", and there may have been additional victims, he said. Dan said it all happened so quickly, the crowds in the busy park hadn't noticed as they ran by.
I don't know how many Libyans there are living in the UK but I wonder whether, and if so how well, this man knew the Abedi brothers, the murderers of the women and girls at Manchester Arena in 2017?