The four men ranging in age from 19 to 35 began their trial before a Bonn state court, charged with assault resulting in death, according to local broadcaster WDR.
Prosecutors accuse the quartet of beating a 40-year-old father, who they knew beforehand, so badly that he died a few days later due to his injuries.
Prosecutors say that last September, the four reportedly went out in central Waldbröl with the intention of “hunting refugees”, after one of the accused claimed refugees had stalked a girl.
Witness statements helped investigators piece together the events: first the four reportedly met up to drink, then they went to search for refugees to “rough up”, carrying a baseball bat and brass knuckles.
"The accusation assumes that their original 'objective' was to go out in Waldbröl to mess with refugees," a court spokesman told DPA.
The four ultimately did find some refugees and got into a fight with them, but the refugees were able to get away, prosecutors say. The quartet continued on, reportedly beating at least one other man bloody before encountering the 40-year-old victim, Klaus B., at a parking area.
They reportedly had already fought a few days before with Klaus B., who was born in Kazakhstan. According to WDR, the four accused also have eastern European heritage.
WDR reports that it seems Klaus B. - who had also been drinking - was at the wrong place at the wrong time, and that it is still not clear why the encounter became so violent.
According to prosecutors, the 19-year-old was the first to hit Klaus B. before the others joined in, employing the baseball bat. Even while the victim was lying on the ground and later tried to flee, prosecutors say the four continued their assault upon him.
The 40-year-old suffered a fractured skull, as well as traumatic brain injuries. He died nine days later in hospital, leaving behind two children and his wife.
His family have been included as co-complainants against the four because their lawyer says the children have been left traumatized by their father's death, especially due to its brutal nature.
“The wife always tells me that she absolutely cannot comprehend how the perpetrators could continue to beat him when he had already long been lying on the ground. And he kept trying to get himself up to leave,” said lawyer Christina Dissmann to WDR.
“They kept going after him and beat him. That is the most difficult part.”