Three people were stabbed to death in a “terrorist incident” at a park in a town outside of London on Saturday, police said. Another three people were also seriously injured in the attack.
After taking over the investigation from regional force, Thames Valley Police, the U.K.’s Counter Terrorism Police declared that the attack was terrorism related on Sunday.
The stabbing took place shortly after a Black Lives Matter rally at Forbury Gardens, a public park in Reading, a large town around 40 miles west of London, at around 7 p.m. local time (2 p.m. ET), Thames Valley Police said in a statement shortly after the incident.
However, the force said that the incident was not connected to the rally and the stabbings happened around three hours later.
A 25-year-old man from Reading was arrested on suspicion of murder and is in police custody, Thames Valley Police said, adding that they had launched a murder investigation.
His name was not released and investigators were not looking for any other suspects, the statement said.
Initially, investigators said the stabbing was not being treated as terrorism.
But after working with Thames Valley Police, Counter Terrorism Police later declared that the attack was “a terrorist incident.”
Chief Constable John Campbell of Thames Valley Police said in a statement that he was “deeply saddened” by the stabbing.
“This was a truly tragic incident and the thoughts of Thames Valley Police are with all those who have been affected,” he added. “Incidents of this nature are very rare, though I know that will be of little comfort to those involved and understand the concern that this incident will have caused amongst our local community.”
Prime Minister Boris Johnson tweeted that his thoughts were with those affected by the attack.
Nieema Hassan, an organizer of the Black Lives Matter protest, posted on Facebook that demonstrators had dispersed by the time of the attack.
“In terms of the protest and people that attended from Black Lives Matter, we’re all safe, none of us are affected,” she said in a video message.
Segilola Arisekola and Mohammed Syed contributed.