Speaking from their home in the West Bank city of Ramallah, Hasan's relatives painted a picture of a man cornered into an act of "lunacy" by the repeated discrimination of his peers and an attempt by the army to force him to serve in Afghanistan.
"They discriminated against him because he was a Muslim," Mohammed Mohammed, one of Hasan's cousins, told the Daily Telegraph. "We're not trying to make excuses for him but what we were told was that he was under a lot of pressure.
"What we imagine is that he could not take this bad treatment and gave vent unfortunately." ...
In the house next door, Hasan's brother Anas had locked himself indoors with his wife, refusing to speak to anyone, including his relatives.
According to his cousins, Hasan was badly scarred by the deaths of his parents in 1998 and 2001. Along with his two brothers, he became increasingly devout, they said.
"They became very religious after their mother died," Mohammed Hasan said. "They were very observant. They prayed a lot."
Yet the two cousins insisted that the major's religion was not tinged with political fanaticism, although they said he had become increasingly withdrawn and uncommunicative in recent years.
Even so, they had little reason to believe that he was a man on the edge.
"Nidal is a very stable minded person," Mohammed Mohammed said. "Why would he kill? He was against violence.
"His actions could have been in self defence â€“ we don't know. Maybe they angered him to the point of cornering him and he felt he had no option."
They angrily rejected suggestions that their cousin's shooting spree had been motivated by a hatred for America or as an act of terrorism.
"My cousin is not a terrorist," said Mohammed Hasan. "He was born in America, he graduated from Virginia (Tech) University. He was proud to be graduate. He was always preaching about the US education system. He was an optimistic person. He loved life."
Although he had always wanted to follow other members of his family into the army, Hasan was shocked that he was never accepted as a true American, the cousins said.
He was constantly taunted and provoked until six months ago, he hired a lawyer to sue the army, the cousins said, explaining they kept in touch with developments in Hasan's life either through telephone calls to him and his family or from Hasan's brother, who returned to the West Bank four years ago.
They heard that he had become increasingly unhappy, both at the treatment of his peers and also because he had been ordered to deploy "in Iraq and Afghanistan". But the two cousins insisted that Hasan's opposition to being sent abroad was as much because he was planning to marry. [Whom?]
The two men also denounced the attention being given in the media to Hasan's religion.
"Had Hasan been a pure American, there wouldn't have been such a fuss about it," said Mohammed Mohammed. "There has been a lot of stress in the media about how he was an Arab, a Palestinian, a Muslim."
"If he had been someone else, he would immediately been identified by the government as a lunatic and the subject would have been closed."
"Our religion does not support violence, as the West believes."