Motjeng Sangma was shot on the leg while Kali Das was kidnapped in Bhajamara in Selsella block in the district, they said.
"The incident took place at around 10:30 am and a manhunt is on to nab those involved in the criminal acts," West Garo Hills Superintendent of Police Mukesh Singh told PTI.
While the police are investigating the reason as to why the school teacher was shot, preliminary investigation revealed that he was misidentified by the militants as the businessman they intended to kidnap.
Considered outlawed in January, GNLA is active in all five Garo Hills districts of the state and parts of South West Khasi Hills district where they were involved in kidnapping, extortion and killing of civilians and security forced engaged in counter insurgency operations in the affected districts.