According to witnesses, one man within the group put his hand on the back of a female passenger, a gesture that she reportedly rejected. The Daily Mail reported that the man then smashed his hand against one of the windows in the train, leading other passengers to react — including one elderly man.
As translated by the Daily Mail, a passenger who took a video of the incident said:
One of these men, in the four seats beside me, was then touched on the head by one of the asylum seekers wearing a brown jacket. He stroked his bald head, to mock him. It was such disrespectful behaviour, the likes of which I have rarely seen before.
The gentleman stood up right away. The asylum seeker then turned, approached the man and grabbed him by the neck. Everyone immediately became involved, with many trying to get in between the pair.
In the video, which has amassed more than 60,000 views on YouTube, one man can be seen holding another from behind. More passengers eventually become involved, with some holding up their hands and pointing at others.
According to the Daily Mail, police are investigating the incident but have not confirmed the identities of the men on board, including whether or not they are, in fact, migrants. 
“Based on the video and the witness account we have decided to open a criminal investigation,” a spokesperson for the Munich police confirmed to the Daily Mail. “We are in contact with a witness, but still need to identify the other people in the video.”
The spokesperson added, “It would appear from the video that the aggressors have Arab backgrounds, but whether they are asylum seekers or not, we can’t say at the moment.”
“It’s mere speculation. We are working to identify them,” the spokesperson said.
Many in Germany have been on edge following reports of multiple sexual assaults on New Year’s Eve — most notably in Cologne, Germany.