The man arrested over the murder of British MP Jo Cox was described by people who knew him on Friday as a loner who battled mental illness, but allegedly had ties to white supremacists.

Identified by the British media as Thomas Mair, the 52-year-old man who is being held on suspicion of killing the popular pro-Europe MP in the northern English village of Birstall on Thursday, had lived in nearby social housing for the past 40 years.

"He was very quiet, he kept himself to himself. He was polite. Didn't drink, didn't take drugs," said Stephen Lees, who has lived on the same estate for decades and said he was friends with Mair's brother.

Sitting outside the sports and social club in the centre of Birstall on Friday, Lees told AFP that Mair suffered from obsessive compulsive disorder (OCD).

"He used to scrub his hands with Brillo pads and nail brushes until they were red raw," he said.

Another neighbour, David Pickles, 62, was quoted in several newspapers as saying Mair was "a bit of a loner, but I could not say he was unfriendly".

The description seems at odds with the frenzied nature of the attack on Cox, whom eyewitnesses said was shot two or three times and then stabbed as she lay bleeding on the pavement.

Mair's brother Scott, 50, told The Sun tabloid that he was "struggling to believe what has happened".

"My brother is not a violent man and is not that political. We don't even know who he votes for. I am visibly shaken at this news," he said.

He confirmed that his brother had mental health problems, and the suspect himself spoke about these in an interview with a local newspaper in 2010.


Neo-Nazi supporter?

But evidence has also emerged linking Mair to white nationalist movements in the United States and South Africa.

The Southern Poverty Law Centre, a US civil rights group, said it had found records suggesting Mair was "a dedicated supporter of the National Alliance (NA), the once premier neo-Nazi organization in the United States, for decades".

It said he had spent more than $620 (550 euros) on reading material from the National Alliance, a group which called for the creation of an all-white homeland and eradication of Jewish people.

The Daily Telegraph newspaper also reported that Mair was a subscriber to S. A. Patriot, a South African magazine published by the pro-apartheid group the White Rhino Club.

A 2006 blog posting attributed to the group, which describes the magazine's editorial stance as being against multiculturalism, named him as one of its earliest subscribers, it said.

But Mair's half-brother Duane St Louis, 41, expressed his disbelief at suggestions of his far-right leanings.

"He's never expressed any views about Britain, or politics or racist tendencies. I'm mixed race and I'm his half-brother, we got on well," he was widely quoted as saying.


Mental health issues

In 2010, Mair spoke to the local Huddersfield Examiner newspaper about his mental health issues.

The report said he volunteered at Oakwell Hall country park, a stately home and gardens nearby, after being a patient at a day centre for adults with mental illness.

"I can honestly say it (the work) has done me more good than all the psychotherapy and medication in the world," Mair was reported as saying.

"Many people who suffer from mental illness are socially isolated and disconnected from society, feelings of worthlessness are also common, mainly caused by long-term unemployment."

Neighbours said Mair had never had a full-time job, and lived in the house he had once shared with his grandmother, who died about 20 years ago.

Mair's mother Mary, 69, was struggling to make sense of what happened. "I don't understand it, I just don't understand it," she was quoted in the Daily Mail as saying.