Last Updated Jun 18, 2016 8:12 PM EDT
LONDON -- The man accused of a murder that has brought campaigning in the country's European Union referendum to a standstill turned his first court appearance Saturday into a chilling spectacle by refusing to state his real identity.
Asked his name in Westminster Magistrate's Court, Thomas Mair said: "My name is death to traitors, freedom for Britain."
The 52-year-old Mair, accused of murdering British Labour Party lawmaker Jo Cox, also refused to reveal his address or his date of birth.
His bizarre performance prompted Deputy Chief Magistrate Emma Arbuthnot to order a psychiatric report into Mair's mental state that may influence how the case against him proceeds.
The comments also raised questions about his possible motive for the crime. Once a suspect is charged, British law restricts what can be published about the case to ensure the right to a fair trial is not compromised.
Mair is accused of using a dagger and a handgun to kill Cox after she got out of her car for a meeting with constituents Thursday in the small town of Birstall in northern England.
She was actively backing the campaign to keep Britain inside the European Union's hard-fought referendum, set for Thursday, and had also advocated better treatment for Syrian refugees, particularly children.
In her political views and in her aid work, she had embraced the value of having a multi-cultural Britain, a stance that is unpopular with some Britons.
Britain has been in mourning since her death, which made her the first sitting lawmaker killed in Britain in a quarter century. Vigils were held in dozens of towns and cities, and flags have been lowered on many official buildings.
Both sides in the referendum campaign shut down campaigning within hours of her death, with major rallies and speeches canceled or postponed. Some low-level campaigning, including the distribution of leaflets, has returned and the "leave" campaign re-activated its Twitter account Saturday.
Analysts predict the harsh rhetoric of the campaign may be toned down in its final days in part because of the broad sense of revulsion that swept Britain after the killing of a popular politician who left behind a husband and two young children.
Cox's sister, Kim Leadbeater, and other family members made an emotional visit to the town center in Birstall Saturday to view the many floral tributes left to the slain member of Parliament. They hugged many who had gathered to pay tribute to Cox.
"For now, our family is broken, but it will mend in time and we will never let Jo leave our lives," said Leadbeater. She said her sister would live on through her husband Brendan and "through her truly wonderful children, who will always know what an utterly amazing woman their mother was."
The emotional response to Cox's death, and the halt in campaigning, has shifted the public focus away from the debate over immigration and economics that had characterized media coverage of the referendum.
Instead, there is reflection on a political culture that seems to have lost its way in a blaze of charge and countercharge.
Former Prime Minister Gordon Brown, writing in The Guardian, said the referendum campaign had been transformed from a discussion about Britain's role in Europe and into a forum on immigration and the people who, like Cox, support immigrants.
"Only by tackling the prejudice and hate that killed her can we do justice to the meaning of Jo Cox's life," he said.
It is not clear what, if any, impact the killing of Cox may have on the referendum vote, which is expected by many observers to be close.
Mair was charged with murder, inflicting grievous bodily harm, possession of a firearm with intent to commit a crime, and other gun-related charges. He was handcuffed to a guard throughout the proceedings.
Mair will be kept in custody at Belmarsh Prison until his next court appearance Monday at the Old Bailey courthouse.
He was not required to enter a plea during the brief session Saturday.
Counter-terrorism police were involved in the investigation looking for possible links to external groups, but the charges filed did not include terrorism offenses.
Police have praised the bravery of a 77-year-old man who tried to aid Cox during the attack and was seriously injured. The man is recovering in a hospital.
The attack has raised security concerns for other members of Parliament who routinely meet with constituents in public meetings.
It has long been a tradition in Britain for lawmakers to hold regular "surgeries" in which they discuss local, national and international issues with residents of their district.
The day before her killing, Cox joined her husband and two young children in campaigning for the pro-EU cause on the River Thames, where the family had lived in a houseboat since her election last year.
The houseboat has now been covered with dozens of floral bouquets left by mourners.