LONDON: The teenager accused in a stabbing rampage that killed three girls at a Taylor Swift-themed dance class in England has been charged with producing the deadly poison ricin and now faces a terror offense, police said Tuesday.

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

Ricin is derived from the castor bean plant and is one of the world's deadliest toxins. It has no known vaccine or antidote and kills cells by preventing them from making proteins.

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

Police stressed while the production of ricin was deemed a terror offence, the July knife attack has not been classed as a “terrorist incident,” which would require a motive to be known.

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