The man's son reported his death to police on October 15th, explaining that he had died several hours after the attack, police reported on Thursday.
According to the son's account, his 51-year-old father was relieving himself near the Johannes Church in Freiburg, in the southwestern state of Baden-Württemberg when the altercation occurred.
When the group of four men saw his father urinating in public, they started by insulting him before physically assaulting him, the son said.
While the father had complained of sharp pains in his upper body after the attack, he never called a doctor or the police.
A subsequent postmortem of the deceased man's body revealed that he had in all likelihood died as a result of his injuries.
Police are now searching for the culprits. Three of the men were around 30 years of age, with one described as unusually tall and thin. Another is described as being around 50 years old. All are said to have been of Mediterranean appearance.