(CNN) -- Robert Enke's widow has told a press conference that the Germany goalkeeper was suffering from depression before throwing himself in front of a train.
An emotional Teresa Enke revealed that the 32-year-old Hannover captain was afraid their adopted daughter, who is eight-months-old, would be taken away if his illness became public knowledge.
The couple's biological daughter died three years ago from a heart problem when she was aged just two.
"I tried to be there for him," said Mrs Enke, choking back tears. "When he was acutely depressive, it was a difficult time. We thought we'd manage everything. We thought with love, we could do it. But you can't."
Martin Kind, chairman of Enke's club Hannover, added in the press conference: "I don't know why and how this happened -- It is a total catastrophe. I am finding it hard to understand. All I can say for sure is that it had nothing to do with football."
Fellow players said they believed that Enke had been suffering depression. "He was unstable," added Kind. "But he kept it under wraps well."
Enke died on Tuesday evening when he threw himself before a train near his Hannover home. Police said on Wednesday they had found a suicide note.
Valentin Markser, a doctor who treated Enke, said the goalkeeper first sought treatment in 2003, when he lost his starting place at Barcelona and developed anxieties and fear of failure.
In the note, Enke apologized to his family and the staff treating him for deliberately misleading them into believing he was better, "which was necessary in order to carry out the suicide plans," Markser said.
"Despite daily treatment, we did not succeed in preventing his suicide," the doctor added.
Enke, who had a good chance of being his nation's leading goalkeeper at next year's World Cup finals in South Africa, is the second Germany player known to have suffered from depression.
Bayern Munich midfielder Sebastian Deisler quit football in January 2007 after several bouts of depression and five knee operations.
Meanwhile, Germany have canceled their friendly match against Chile on Saturday in the wake of Enke's death.
The president of the German Football Federation (DFB), Theo Zwanziger, told a press conference the players "needed time to come to terms with the death of Enke."
Germany national coach Joachim Loew said the team could not just go back to business as usual.
"We have lost a friend, we deeply mourn Robert Enke," Loew said. "I feel completely empty. He was a great guy. He had incredible respect for others. We will miss him, as a top-class sportsman and an extraordinary man."
Meanwhile, hundreds of fans and former teammates of Enke gathered to lay flowers, light candles and sign a book of condolence outside Hannover's Niedersachsen Stadion in tribute.
The club's official Web site has been converted into a single-page memorial.
The shot-stopper had also appeared for Carl Zeiss Jena, Borussia Monchengladbach, Benfica, Barcelona, Fenerbahce and Tenerife.
His teammates were stunned by news of his death.
"We are in a state of shock," said team manager Oliver Bierhoff in a statement from the German Football Federation. "It is beyond words really."
"I'm stunned. I don't know what to say," captain Michael Ballack told the Bild daily.
Football commentator and journalist Rafael Honigstein told CNN International that Enke was on course to be picked as the number-one choice for next summer's World Cup finals in South Africa.
Enke had missed Germany's last four matches because of a bacterial infection, but had recently returned to action with Hannover. "It's been well documented that he had a tough time," Honigstein said. "People knew it was a terrible, terrible tragedy for him."