Swapan Murmu, who filed the case on behalf of the Santals in Gaibandha after the Nov 6 mayhem, appears to be missing.
His mother Isha Rani Murmu said that they have failed to locate Swapan for the last eight days.
"We don't know if he filed any case. He used to make bamboo products but we can't find him," she said.
Swapan, who hails from Mualipara, had filed the case ten days after the mayhem that left three Santals dead and scores of their houses burnt on Nov 6.
He did not name anyone but filed the case, blaming 500 to 600 unidentified persons for the mayhem unleashed on the Santals around Sahebganj sugarcane plantation at the district's Gabindganj Upazila.
Police have so far arrested around 20 people for suspected involvement in the violence.
Gaibandha MP Abul Kalam Azad and local Union Parishad Chairman Shakil Akhand Bulbul have been accused by the Santals for provoking the violence against them.
But these Santals have also expressed reservations about the case filed by Swapan Murmu.
Swapan's wife Jyotsna Mardi said her husband left their house eight days ago, saying he is going to work.
We have not informed the police or filed a case," said Jyotsna.
Gabindganj police OC Subrata Kumar Sarkar said they have received no information of Swapan Murmu gone missing.
In 1962, the 'Rangpur Sugar Mill' acquired 1,840 acres of land in 18 villages occupied by Santals and Bengalis for sugarcane farming at Gobindaganj.
The Santals now want the land back as it had been leased out for farming tobacco and paddy, which they say violates the deed of acquisition.
The Santals reoccupied part of the land earlier this year and planted crops beside the sugarcane plantation.
On Nov 6, the sugar mill management conducted an eviction drive. A clash erupted and the houses of Santals were vandalised and looted.
Police claimed they opened fire to stop the clash, but three Santal men died and many others were injured. During the clash, houses of Santals were ransacked and looted.
PLANTING SUGARCANE STARTS
The Rangpur Sugar Mill management has started planting sugarcane on the seven acres of land, from which the Santals have been evicted.
The Santals continue to claim the land is theirs.
"From Friday, planting on sugarcane has started on land abandoned by the Santals," the mill's Managing Director Mohammed Abdul Awal said.
He said that the mill management has handed over 56 sacks of paddy to the Santals. In the last two days, the Santals say they have received 82 sacks of paddy in all.
"Once all of it is received, we will sell them and share the proceeds amongst ourselves," Santal leader Anchen Hembrom said.
The High court had ordered that either the Santals be allowed to harvest the crop or the Sugar Mill should organise the harvesting and hand over the crop to the Santals, according to bdnews24.com.