The trial began Monday for Axel Rudakubana, 18, who is accused of carrying out a stabbing at a dance party last July in the northern English town of Southport that left three children dead and 10 others injured.

Mr. Rudakubana is facing three murder charges for the deaths of Bebe King, 6, Elsie Dot Stancombe, 7, and Alice da Silva Aguiar, 9, who were participating in a Taylor Swift-themed dance and bracelet-making class during recess.

He is also accused of trying to kill 10 people, including eight children and two adults, and being found with a knife in the attack on July 29.

After the police stabbed him, they searched Rudakubana’s house and said they found ricin, a deadly poison, and a PDF file titled “Military Studies in the Jihad Against the Tyrants: The Al Qaeda Training Manual.” mr. Rudakubana then they are paid in the production of natural poisons and “having information of a certain kind that may be useful to a person who is committing or planning a terrorist act.”

However, so far the authorities have not declared the case as terrorism. Serena Kennedy, chief constable of Merseyside Police, who oversees policing in the area, he said in his voice in the month of October that “in order for a story to be said to be a terrorist, it is necessary to establish its reasons.” He added: “We strongly warn anyone who claims to have a problem in this matter.”

Not guilty pleas have been entered on behalf of Mr. Rudakubana in all these cases. Throughout the trial so far, he has refused to speak.

The trial will take place at Liverpool Crown Court and is expected to last around four weeks.

Mr. Rudakubana was born in Cardiff, Wales, to Rwandan parents. He was living in Banks, a village north of Southport, at the time of the attack.

Last week, Britain’s attorney general, Richard Hermer, gave it legal advice to remind social media users and the media about the dangers of contempt of court and to warn that false or speculative comments may influence the judge’s opinion. Anything that would suggest or suggest that Mr. Rudakubana is guilty could affect the prosecution of his case, he said.

After the Southport attack, Britain was rocked by a series of terrorist attacks, with information about the identity of the attacker spreading on social media and messaging apps. False claims that the suspect was an undocumented immigrant or asylum seeker were recently promoted by immigration activists and the right-wing.

Many people, including neo-Nazishe was found to have helped control the riots, which included attacks on mosques and hotels where asylum seekers were staying, resulting in many police injuries.

Mr. Rudakubana was 17 years old at the time of the attack and under English court rules, he would not normally be identified until he turned 18. to try to combat the spread of falsehoods.

Since the riots started last summer, hundreds of people have been there was called for their involvement in violent unrest across the country, and many people have been sentenced to prison terms.

Yvette Cooper, the British home secretary, said in a statement on Monday morning that the trial would be “a very sad and painful time for the families of Alice, Bebe and Elsie, the survivors, as well as the people of Southport and the whole country.”

“The most important thing for all of us is to ensure that the law can take its course, to respect the difficult work that the court has to do so that the case is fair and justice is done,” he said.