The cop reportedly boarded the train from Kannur to check tickets.
A video from Kerala - that shows a policeman repeatedly kicking a passenger allegedly traveling without a ticket in a train - has led to the suspension of the cop after it was widely shared on social media, triggering huge criticism.
In the nearly 20-second video, an angry cop is seen hitting the passenger who is sitting helplessly on the floor. The cop then kicks him and the man falls on the floor.
Another cop and a railway official are among the bystanders.
The incident happened on Mavali Express on Sunday.
The cop reportedly boarded the train from Kannur to check tickets. He has been accused of thrashing the man when he could not give the tickets. They also believed that the man was drunk, news agency PTI reported.
On social media, people demanded action against the bystanders too.
"A passenger who was travelling in Maveli Express train yesterday had been brutally beaten by the police. Please dismiss the TTE from the service for witnessing the incident but still not stopping the cop," read a tweet.
Political opponents criticised the state government too. "Has Pinarayi's Police gone bonkers? They runaway from criminals & batter the common man. The assault on the passenger in Maveli express w/out ticket was uncalled for. Instead of legally tackling the issue it has become a habit for #Kerala police to flex muscles on common man. (sic)," Kerala BJP leader S Suresh said.
Congress took out a protest march in Kannur. VD Sateeshan, Leader of Opposition, slammed the police, alleging it was being ruled by party men rather than police officials.
Last week, reports said, a team of the state police made a foreigner empty liquor bottles he had purchased from a state-owned liquor outlet for New Year's Day celebrations, a video of which also went viral.
The state government had ordered a probe.
(With inputs from PTI)