Ireland fan James Nolan is believed to have drowned as a result of a tragic accident, with no evidence of an assault being involved.
The findings were made after an autopsy of the 21-year-old’s body in Bydgoszcz, Poland, yesterday.
Mr Nolan, from Blessington, Co Wicklow, had travelled to the Eastern European country with a group of friends in what Blessington FC chairman Vincent Balfe said was a "trip of a lifetime that turned into a nightmare".
After socialising in the city on Saturday night, he was separated from his friends at about 1.30am on Sunday.
His body was found in a nearby canal on Wednesday. When divers recovered his body they found the IT Tallaght student’s credit card and other belongings untouched, suggesting he may have inadvertently fallen into the canal and was not robbed or assaulted.
Leon Bojarski, Bydgoszcz’s chief prosecutor, said authorities "are doing everything to return the remains to the family as soon as possible".
At a press conference in Bydgoszcz last night, Mr Nolan’s brother Andrew thanked everyone who had helped in the search.
"It is very, very much appreciated. Without this kind of support it would be very difficult to get through this situation."
In a touching mark of respect to the 21-year-old, Bydgoszcz was yesterday decked out in the Irish Tricolour as Polish citizens sought to offer some comfort to his loved ones.
The city’s mayor Rafal Bruski has called for a minute’s silence in honour of Mr Nolan at one of the Euro 2012 quarter-finals taking place until Sunday.