BUILDING A PORTRAIT OF NEW YORK GUNMAN

A day after a gunman killed 13 people and himself at an immigration centre in New York state, the BBC's Jon Donnison in Binghamton looks at what has been revealed about the killer and his motives.
Jiverly Wong is just the latest person in America to become infamous because of a mass shooting.
Investigators here are slowly building up a picture of the man behind one of the worst crimes this area has ever witnessed.
At a packed news conference at Binghamton City Hall, police confirmed that the 41-year-old, who used the alias Jiverly Voong, was the man who committed mass murder here on Friday morning.
Wong, a Vietnamese-American, lived with his parents and his sister in a small town just down the road from Binghamton.
Remarkably, police said people close to Wong had told officers that they were not completely surprised by his behaviour.
Binghamton's Mayor Matthew Ryan said police were now trying to carry out a "psychological autopsy" to work out what had led Wong to kill so many.

Officers are talking to his family and searching his house to find any clues to his motives.
Binghamton's police chief, Joseph Zikuski, said that until a month ago Wong had taken English classes at the immigration centre but quit after complaining that he had been made fun of.
Mr Zikuski said Wong felt other students had mocked him because of his poor English.
He also confirmed that Wong had recently lost his job at a company called Shop-Vac, which makes vacuum cleaners.

Some people in Binghamton are now asking whether the tough economic times could have pushed him over the edge.
Sheltering from the rain in a doorway, smoking a cigarette, I found Darlene Trunkowski, who speculated that economic pressures could have been a factor.
"The times are so bad," she said. "I think that's why a lot of people are so stressed. People are losing their jobs and they don't know what to do."
"Is this the solution?" she asked herself. "No, but it's very sad."
A former co-worker at the vacuum cleaner factory, Donald Ackley, told ABC news that Wong had been a loner who often seemed anxious.
"He was real nervous, real high strung. He worked real hard," he said.
Police believe the attack must have required a lot of planning and that Wong came prepared for a fight.
"Mr Wong arrived at the centre wearing body armour, which would tell us that one point in his thinking process he was going to take the police on," Mr Zikuski said.
Mr Zikuski also referred to a protective order against Wong relating to a divorce in California, but gave no further details.
Most of the dead were immigrants to the US who were at the American Civic Association centre taking classes to try to obtain US citizenship.
Four people remain in hospital, two of them in a critical condition.
In an emotional statement, Angela Leach, who ran the centre, said the town must now pull together to support the immigrant community.
"Whatever drove this individual to do what he did I cannot possibly fathom," she said, "but we will come out of our grief and sadness more resolute in our mission to help people realise the dream of American citizenship."
BBC NEWS REPORT.