The British police announce this. The new charges come after a jihadist terrorist manual was found in the man's home. The toxic substance ricin was also found in the man's home.
The man has already been charged with murder and attempted murder.
Since the motive behind the deadly attack is unknown, this has not been classified as a terrorist crime, the police emphasize.
Three girls were killed when the man, armed with a knife, attacked a Taylor Swift-themed yoga workshop in the town in northwestern England. Ten people, eight children and two adults, were injured.
The attack was used by what the police suspect were right-wing extremist activists to stir up anger against migrants and Muslims, driven by false rumors on social media. Violence spread from Southport across England and Northern Ireland and lasted for over a week.
Over 50 police officers were injured in the riots.
