Their report confirmed what a 16-year-old French exchange student who witnessed the brutal crime at the Solln station told daily Bild.

“As I came up to the train platform, the two were already beating on the man, kicking him with their feet. About 15 people were standing around not doing anything,” the student told the paper, adding that he saw the event peripherally and didn’t realise how severe it was until he saw the man fall to the ground.

“At some point the man collapsed and hit the back of his head against the guard rails in the process,” he told the paper.

According to news agency DPA, public prosecutors are investigating whether witnesses could have prevented the man’s death, which has made national headlines since it occurred on Saturday afternoon.

A 17 and 18-year-old have been accused of murder for beating businessman Dominik B. at the stop after he tried to protect a group of four youths who were being bullied by the two teens on a train,

Police said that the young men had been threatening and demanding money from a group of younger teenagers at an S-Bahn station before following them onto a train, where Dominik B. intervened.

He called police on his mobile phone and offered to leave the train with the children to make sure they were safe.

As they left the train at the Solln train station, Markus S. and Sebastian L. followed the man and attacked him. They hit and kicked Dominik S. some 22 times within just a few minutes. The children who had exited the train with the man attempted to stop the attackers unsuccessfully, according to state prosecutors. He died of his injuries in a nearby hospital a few hours later.

Police said Monday they had arrested a third suspect, 17-year-old Christoph T., for allegedly initiating threats against the group of children after they refused to give the older teens €15. He is accused of extortion. Witnesses also reported seeing him hit the group of children twice. The teen allegedly boarded a different train while his friends followed the younger children onto another – where they encountered their middle-aged victim.

All three of the teens in police custody have reportedly had brushes with the law in the past due to theft, assault and extortion. Two of the accused also reportedly suffer from substance addiction.