Greece's Food Inspection Agency confirmed Wednesday that bottled water given to players from a visiting soccer team in April had been laced with a powerful psychiatric drug.
The agency said it planned to give the test results to a prosecutor for a possible criminal investigation into the incident, which occurred during a first-division game between host Akratitos and Iraklis.
Greece's Association of Professional Soccer Clubs, or EPAE, said it told Akratitos it was being investigated.
"EPAE, acting in the framework of the law and regulations, told the home team it was being looked at," it said in a statement.
Although announcement comes a little more than two months before the start of the Olympics in Athens, the games' organizing committee ruled out the possibility of such an incident occurring during the Aug. 13-29 event.
All food and water for athletes will be subject to random inspections for poison or any substance that could make an athlete test positive in a doping test, officials said.
The water was tested after a sealed bottle was turned over to police by Iraklis staff. Akratitos won the match 1-0, but was relegated to the second division at the end of the season after finishing 14th in the 16-team league.
The agency said the results showed that a hypodermic needle was used to inject haloperidol, a powerful depressant, into the bottle. The agency did not say if the quantity it found was enough to affect an adult.
"Haloperidol is a powerful chemical substance used in medicine and is considered a powerful neurological drug given in serious and long-term cases of psychosis," the agency said. "This case will immediately be turned over to a prosecutor."
A probe into the allegations could lead to other examinations of Akratitos.
After an April 17 game between Akratitos and Ionikos, a suburban Athens club, at least one player was hospitalized and doctors were unsure what caused him to pass out.
When Akratitos played Kalithea, another Athens team, the coach was hospitalized for three days after losing consciousness following the game. Akratitos beat Ionikos 3-0 and played to a scoreless draw against Kalithea.
The reasons for the attempt to drug the players remains unclear, but suspicions have fallen on attempts by Akratitos to remain in the lucrative first-division.
"We have nothing to fear and want to shed as much light on this case as possible," Akratitos said in a statement.
Sports Minister Giorgos Orfanos said the incident "blackened" the reputation of Greek soccer and promised that justice would be meted out.
"Everyone can rest assured that justice will be done and those responsible punished," Orfanos said.
In its statement, EPAE said the allegations "by far surpasses the limits of the imagination."
"Such incidents, even though rare and isolated, blacken soccer and the trust of the clubs for their opponents," the association said.
The players union described the incident as "shameful and disgusting."
"This is the most serious incident which has ever occurred on Greek soccer fields," the players union said. "It is shameful and disgusting to endanger the health of professional soccer players by giving them forbidden and dangerous drugs."