The three metal workers, colleagues aged between 36 and 48, were found dead in the sauna at the oldest man's home in the western town of Ennepetal on Dec. 8.
Prosecutors in Hagen said Friday that tests have determined the men's blood-alcohol level was more than four times the legal limit to drive.
They say they believe the three men passed out in the sauna and then died of heart failure an undetermined time later. Prosecutors see no evidence of foul play.
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