The suspect arrested by police after Labour MP Jo Cox was shot and killed in the street in Birstall, West Yorkshire has been named as Tommy Mair.
Here's what we know about him:
Who is he?
Tommy Mair is a 52-year-old man who has lived in the same house in Birstall for more than 30 years.
Neighbours say he has lived alone for the last two decades, since the death of his grandmother, and that he tends to "keep himself to himself".
What else do we know about him?
According to a newspaper report about volunteering, published in the Huddersfield Examiner in 2011, Mair used to volunteer at Oakwell Hall country park in Birstall and is a former patient of the Mirfield-based Pathways Day Centre for adults with mental illness.
In his interview with the paper he referred to his mental health issues as he explained that he felt volunteering "has done me more good than all the psychotherapy and medication in the world".
Mair was quoted 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."
What do people who know him say?
His brother, 50-year-old Scott Mair, said the family was "struggling to believe" what had happened, as his brother was "not a violent man and not that political."
Speaking to The Sun, he added: "We don't even know who he votes for. I am visibly shaken at this news. I am so sorry for the MP and her family."
Mair had a "history of mental illness", he said, but "has had help".
And his half-brother Duane St Louis said he believed Mair "wouldn't hurt a fly".
"He's never expressed any views about Britain, or politics or racist tendencies," he said. "I'm mixed race and I'm his half-brother, we got on well."
Meanwhile, neighbours have described Mair as a "loner" who liked gardening but "kept himself to himself".
David Pickles, who has lived near Mair since 1975 said he "still can't believe" Mair has been arrested and that he did not know of any connection between his neighbour and Ms Cox.
Another neighbour, who did not want to be named, said they had known him since they were young and were "shocked" at the news.