The Gurgaon Additional District and Sessions Court on Saturday sentenced 13 accused in connection with the violence and rioting at Maruti Suzuki plant in Haryana’s Manesar district in 2012. Four others got five-year prison term each. The court said that 14 others had already served the sentence and they could be fined and released, reported Hindustan Times.

Defence lawyers say there are several “internal contradictions and falsehoods” in the prosecution’s case and have questioned the fairness of the police investigation.

Maruti Suzuki Workers Union members and the workers’ former colleagues who were present in court on Saturday announced a one-hour “tool down” – stopping of work – on Saturday night in protest against the verdict. It will affect all four plants of Maruti Suzuki India Limited, as well as two other factories of vendor companies of Maruti.

Earlier, on March 10, the court had acquitted 117 of 148 workers after a four year long trial after it did not find any evidence against them. While 13 people were convicted for murder, 18 were held guilty of rioting and other crimes.

The case dates back to August 2012, when senior manager Awanish Kumar Dev died and several others were injured in a fire that broke out at the plant during a clash between workers and the management.

Tension had been brewing in the factory for a while before the incident. In 2011-2012, more than 4,000 workers went on strike three times to demand better work conditions and the right to form an independent trade union. Even after the union was formed, relations between the workers and the management continued to be strained.