Jose Geraldo Amorim-Pimenta, 42, was still in love with his wife, Natasha, 34, according to his flatmate, and had been depressed since learning of the relationship 10 days earlier. His three-year-old son, Jubrya, was described as "very critical" in hospital last night. His five-year old son, Asunto, died in the fall.
Jose Brito, 29, who shared a flat with Mr Amorim-Pimenta in Manor House, north London, said that the couple's marriage had ebbed and flowed for several years but finally came to an end when Mr Amorim-Pimenta learnt that his estranged wife was seeing one of his friends.
Mr Brito said: "Jose and Natasha separated several years ago but they had still been involved with each other. She would often bring the boys round to his flat and would often stay over.
"I think he was still in love with her but she started seeing a friend of his and things came to a head about 10 days ago.
"Jose was very upset for several days afterwards about Natasha seeing this other guy, and he let himself go a bit. But then he snapped out of it. He smartened himself up, shaved, and put on clean clothes.
"Just the day before this happened, he told me that he was 'born again' and had put it all behind him. He went to pick up the boys yesterday morning and we were all in the flat together.
"The boys were playing around in the living room and there was a happy atmosphere. It was a completely normal weekend. I left at about 12 noon and there seemed nothing wrong."
Witnesses have told police that Mr Amorim-Pimenta told his sons to say goodbye before he threw them from the balcony at lunchtime on Saturday.
Margaret McBrian, 58, said: "He took the children along the balcony to overlook where a friend of his was about to leave on a motorbike.
"He told the children: 'Say goodbye to your friend'. They said goodbye and he threw them over one after the other and then threw himself down, head down.
"It was all over in a second. There was nothing anyone could do. We were all very shocked. I went over to the bodies and knelt down and prayed the children would live. Then I saw a toe start wriggling in a sandal."
Paramedics summoned an air ambulance to ferry the boys to hospital but their father was already dead.
Tricia Page, 31, who lived next door to the dead man, said: "The children used to play with my boys. They were never any trouble. We cannot believe what has happened. He seemed an ordinary, pleasant man."
Last night, the Royal London Hospital described Jubra as being in a "very critical" condition on a life-support machine. Gavin Bland, the hospital general manager, said: "The little boy is still in a very critical condition. He is on a full life-support machine. His mother has not left his bedside all night. It is too early to speculate whether he will recover or not."
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