The man arrested over the stabbing attack in Reading that left three people dead was known to UK security services.
That's according to reports, which said Khairi Saadallah was on the radar of MI5 in 2019 over concerns that he'll travel abroad "for extremist reasons". That inquiry, however, was closed without any action as no major threat was identified.
The 25-year-old, who was initially arrested on suspicion of murder, has now been re-arrested under a Terrorism Act.
Police added that he was acting alone.