The former Premier League footballer George Baldock “most likely” died after drowning in the pool of his seaside apartment in southern Athens, Greek authorities believe.

Police investigating the circumstances of the former Sheffield United and Greece defender’s death said there was no suggestion of foul play “at least at this stage of the inquiry”.

A state-appointed coroner who conducted an initial examination of Baldock’s body at the apartment in Glyfada, less than half an hour’s drive from the centre of Athens, reported no signs of bruising or other wounds. But it was unclear whether the 31-year-old was alone or if his death had been triggered by “sudden collapse”.

The fall-back, who was born in England and had Greek roots on his father’s side, moved to the Greek capital after signing for Panathinaikos in the summer.

“He was found lifeless at the bottom of the pool and pronounced dead at 22.38 last night [Wednesday],” a police source involved in the inquiry told the Guardian. “All the evidence, so far, points to death by drowning.”

The initial findings were supported by the results on Thursday of a postmortem conducted at the University of Athens’ hospital mortuary.

Forensic scientists were quoted as saying they believed Baldock had been dead “for five hours” before his body was discovered by the owner of the first-floor apartment, who jumped over a fence to access the property. The man had been asked to look for the footballer by Baldock’s concerned wife, who had remained in England with the couple’s young son, after her repeated telephone calls had gone unanswered.

Panathinaikos fans streamed to the Glyfada apartment building on Thursday to pay tribute, with many in a state of apparent shock. Baldock, who last played for the team against their great rivals Olympiakos in the Super League on Sunday, had won the respect of fellow players and was described as being “much loved”.

A police investigation, launched within minutes of his body being discovered, is under way, with the apartment sealed off. “An investigation is now being carried out,” said a senior police official, speaking on condition of anonymity. “Witness statements have been taken from neighbours and footage from CCTV cameras around the building will be inspected. Was he alone? That is the question we all want to answer.”

The Football Association said there would be a period of silence before Thursday’s Nations League match between England and Greece at Wembley, and that players of both sides would wear black armbands.