Bankura Superintendent of Police Pranav Kumar said: "The victim was identified as Charu of Punishole in Onda police station area."
"We have rescued two other youths, who were accompanying him and were also attacked. They have been shifted to hospital but are yet to be identified," he said.
"Prima facie, the trio tried to molest the girl. We have initiated an investigation into the matter to find out the motive," said the police chief.
A senior police officer of Saltora police station in the district said: "The three youths riding two motorcycles tried to abduct the Class 8 student in Saltora village while she was going to Gobra Girls' High School near Horaka village."
When agricultural labourers working in the fields saw the youths forcing the girl to sit on a motorcycle, they chased the youths and caught them, police said.
Police said the youths were later taken to a political party's office in Saltora. As the news spread that some youths had tried to abduct a local girl student, people started gathering near the office. Later, the local people attacked the trio.
The youths were severely beaten up by a mob. They were hit with sticks and iron rods resulting in the death of one of them. The agitated people also set their motorcycles on fire, said the police officer.
The officer said: "We rushed to the spot and rescued the two other youths and they were admitted to a local hospital in critical condition."