The police also recovered from the accused an iron rod and a brick that was used to kill 26-year-old Dileep Saroj, police said.
Shankar was taken into custody from the house of Chandra Bhadra Singh, a political activist.
The other three accused -- Gyan Prakash Awasthi, Ramdeen Maurya and Munna Chauhan -- have already been arrested.
After a scuffle over a trivial issue at an eatery last week, Saroj was brutally assaulted by four men led by Singh. The LLB student had gone into a coma and later died.
The killing had been filmed by a passer-by and the clip went viral, leading to outrage. His autopsy showed 30 injuries on his body, including several fractures.
(Only the headline and picture of this report may have been reworked by the Business Standard staff; the rest of the content is auto-generated from a syndicated feed.)