LONDON (AP) — The teenager accused in a stabbing rampage that killed three girls at a Taylor Swift-themed dance class in England has been charged with a terrorism offense, police said Tuesday.

Merseyside Police said that Axel Rudakubana, 18, who is charged with murdering three girls and stabbing 10 other people, was producing the deadly poison ricin that was found in his home.

Chief Constable Serena Kennedy said Rudakubana also had an Al-Qaida jihad training manual.

Rudakubana, who police said was born in Wales, already faced three counts of murder over the deaths of Alice Dasilva Aguiar, 9, Elsie Dot Stancombe, 7, and Bebe King, 6, in the seaside town of Southport in northwest England.