Bhopal, March 6: A tractor trolley that was allegedly smuggling sand crushed to death a Madhya Pradesh forest guard after being challenged today, prompting the police to charge the driver with murder.

The state's notorious sand and mining mafia has been accused of running over and killing several forest and police officials, including an IPS officer, Narendra Kumar, in Morena in 2012.

Early today, forest guard Narender Sharma, 45, had tried to stop four sand-laden tractor trolleys at Raira in Gwalior district, eyewitnesses have told the police.

When Sharma jumped on one of the tractor trolleys, driver Lala Gurjar, 19, allegedly stepped on the accelerator. Sharma fell and was run over, Gwalior police chief H.C. Mishra said.

Sharma had been part of a joint drive by the police and the forest department against illegal sand mining on the Chambal's banks.

Sand is a key material for the construction, glassmaking and computer industries as well as many others.

The illegal sand-mining industry in Madhya Pradesh is a threat to the environment and is believed to be controlled largely by politicians and their relatives.

Mumbai-based anti-sand-mining activist Sumaira Abdulali said the racket could be stopped only if the local populations got vigilant, and the state and central governments changed the laws.

Six months after IPS officer Kumar's alleged murder, Abhishek Singh, a trainee IAS officer posted at Morena, was attacked when he tried to prevent sand-mining near the Chambal Gharial Sanctuary.

In June 2012, the CBI chargesheet termed Kumar's death an "accident". In December that year, the CBI court rejected a petition from Kumar's father seeking a murder trial. Eventually, accused Manoj Gurjar was found guilty of culpable homicide and sentenced to 10 years.

A year ago, constable Dharmendra Chauhan was run over by a dumper carrying illegally mined sand when he tried to stop it in Morena.