Maruti Suzuki India shut down its Manesar plant in Haryana indefinitely after its workers went on the rampage, killing one person, injuring 50 executives and setting more than 100 vehicles ablaze on Wednesday.
The injured included some Japanese nationals.
The Haryana Police found a body in the conference room but are yet to identify the person, who was charred beyond recognition.
Though the cause of the violence is not known, workers alleged a supervisor made casteist remarks against a Dalit worker and slapped him.
The management then suspended the worker and this could have sparked the violence, sources said.
"The supervisor made casteist remarks against a permanent worker who belongs to the scheduled caste category. When we protested, the management misbehaved with us and suspended the worker," Maruti Suzuki Workers' Union general secretary Sarabjeet Singh told PTI.
Police commissioner KK Sindhu said the body was recovered from the place where the workers had burnt the structure. Raids are on to arrest the workers, he added.
The mob attacked executives when negotiations were underway between the union and the management.
The Manesar unit produces 1,200 cars a day and witnessed three rounds of labour unrest last year.