Eight migrant labourers were shot dead in their camps at a remote coal mine in the South Garo Hills district on Sunday night, while another was lynched by a mob last Friday at Tura, the headquarters of West Garo Hills district.
"We are yet to make any arrests. Cases of murder, attempt to murder, theft and criminal conspiracy have been registered in the incident," South Garo Hills district SP Davis Marak said.
The district administration has also ordered a magisterial probe into the incident. Additional district magistrate Davidson Sangma, who is heading the inquiry, has been given 15 days to submit the report.
Police have also registered six cases in connection with the Tura incident in which a migrant labourer was killed by a mob after he was allegedly caught molesting a mentally disabled woman.
West Garo Hills DSP Mukesh Singh, who is camping in the plain belt areas of the district neighbouring Assam, said life has been affected in the aftermath of the two incidents. He said night curfew under Section 144 of the CrPC has been imposed from 6pm to 6am to prevent any untoward incident.
Inspector general of police (Western Range) H Nongpluh said normalcy has returned as markets along the interstate boundary with Assam have begun to open for businesses. He however, said police and paramilitary forces are alert.
Chief minister Mukul Sangma said the district administration has issued an advisory for migrant labourers to move to safer grounds. More than 11,000 migrant labourers from Assam have been safely evacuated under police escort from mining and construction sites in the two affected districts to their homes, a senior home official said.