A criminal investigation has been launched into the mysterious bike crash and missed drugs test of Kostas Kenteris and Katerina Thanou.
The Greek sprinters pulled out of the Games in Athens after an International Olympic Committee hearing on Wednesday.
They failed to attend a test after an road accident involving a motorcycle.
Prosecutor Spyros Mouzakitis will consider whether injuries reported by the athletes were caused by the crash and how they came to miss a dope test.
Mouzakitis will supervise the inquiry after being handed reports from the traffic police, a medical examiner and others, judicial officials said.
He has also expanded an inquiry into the past of the sprinters' coach, Christos Tzekos, after claims he had imported unlicensed products for his food company.
The investigation could result in the prosecution of the sprinters and the coach if it determines that laws were broken.
Kenteris and Thanou also face a long wait to see whether they receive a ban from athletics governing body the IAAF, which will discuss the matter on 26 August.
They are likely to be suspended until the investigation concludes - which could be weeks after the Olympics end.
As well as missing a doping test in Athens, Kenteris and Thanou had also failed to attend tests in Tel Aviv and Chicago in recent weeks.
Kenteris, the Olympic 200m champion, and Thanou, who won silver in the women's 100m at Sydney, were due to attend a drugs test on last week on Thursday but failed to show up.
They were then involved in a motorcycle accident in an Athens suburb and were taken to hospital with various cuts and bruises.
Greek police, however, have launched an inquiry into the accident after failing to find any witnesses, including the driver who is said to have taken the pair to hospital.
Hospital officials have so far refused the police permission to quiz the athletes further on their accident.