Robert Enke, the Hannover and Germany goalkeeper who was expected to be part of his country's World Cup squad next summer, has died after being hit by a train close to a level crossing near his home.

Police said on Wednesday that Enke left behind a suicide note, but would not say where the note was found. Jörg Neblung, a close friend and adviser of Enke, confirmed that the 32-year-old had killed himself. "I can confirm that it was suicide," he said. "Robert took his own life. A press conference in Hanover will reveal more details."

"We are all shocked," said the national team's general manager, Oliver Bierhoff, who cancelled today's planned training session. "We are lost for words."

A police statement confirmed that the incident happened in Neustadt-Eilvese and Enke died at the scene. Hannover's president, Martin Kind, said the goalkeeper had been "unstable" recently but that it had not been publicly noticed. "This is a tragedy," Kind added.

Enke's car was found near the scene, unlocked, with his wallet on the seat. The two train drivers reported seeing a man on the tracks and applied the brakes while travelling at about 100mph but could not stop in time, police reported.

Enke's daughter Lara died in 2006 of a rare heart condition when she was two and he leaves a wife, Teresa, and an eight-month-old daughter they had adopted.

Germany's players and staff were informed after training in Bonn. Enke's death may bring about the cancellation of Saturday's friendly against Chile.

Enke had been diagnosed with a bacterial stomach virus several weeks ago and did not play for Hannover for two months, although he reappeared for Sunday's 2-2 draw with Hamburg. He was not selected for the friendlies against Chile and Ivory Coast next Wednesday although Germany's coach, Joachim Löw, had said Enke – who won eight caps after making his debut in 2007, the last of them against Azerbaijan in August – remained the leading candidate to be his No1 in South Africa.

Understudy to Jens Lehmann at Euro 2008, he was in line to secure the starting place before falling ill and missing the last three qualifiers. In that time Rene Adler increased his chances of taking the role. Enke made 196 Bundesliga appearances, also playing for Borussia Mönchengladbach after starting in East Germany with Jena. He had spells at Tenerife, Fenerbahce, Barcelona and Benfica.

Barcelona had a minute's silence in his honour before their Copa de Rey match against Cultural Leonesa, while Tenerife paid tribute to their former player. "Tenerife want to convey their condolences and sympathy following the recent death of the German goalkeeper Robert Enke," a statement said. "Tenerife will have a minute's silence in the next game against Sevilla and will wear black armbands."

Fans gathered at Hannover's stadium to lay flowers and light candles at the gates in memory of their captain, who had been with the club since 2004, while other high profile figures from Enke's career also paid tribute.

Former Germany captain and coach Franz Beckenbauer said on the DFB's official website: "I am infinitely sad. When you receive news like this all other problems pale into insignificance."

Schalke striker Kevin Kuranyi told Bild newspaper: "This can and must not be true. Robert was such a great bloke. I don't know how I will tell my wife. She is very good friends with Robert's wife. I feel for his family."

Hamburg captain David Jarolim added: "I can hardly breathe because I'm so upset. This is a real tragedy, I can hardly believe it. First his little daughter dies and then this."