The mob, suspecting that the residents of the red light area were involved in the killing, had beaten up the Dalit woman before tearing off her clothes and parading her naked on the streets.
Additional District and Sessions Judge Ramesh Chandra Dwivedi awarded seven years imprisonment to five of the 20 accused while the remaining 15 were sentenced to two years in prison.
All had been convicted on November 28.
The incident took place on August 20 in a red light area close to a railway track where the body of Vimalesh Sah, a resident of Damodarpur village, was found a day after he had gone missing.
The mob, suspecting that the residents of the red light area were involved in the killing, indulged in large-scale arson and beat up the Dalit woman before tearing off her clothes and parading her naked on the streets.
The five who have been awarded seven-year terms have also been slapped with a fine of Rs.10,000 each and the rest would have to pay a fine of Rs. 2,000 each.
All the 20 convicts have been held guilty under the SC/ST Act.
Hailing the speedy trial, Bihar Deputy Chief Minister Sushil Kumar tweeted: “It is a fresh example of the high benchmark of rule of law set by the NDA government. All the guilty have been punished within 100 days. But those beating their chests on law and order remain oblivious to the long arms of law”.