Two motorcycle-borne assailants opened fire from an AK-47 rifle at Ahmed while he had gone to buy tiles at a shop in Titaguri Market, killing him on the spot and seriously injuring the shopkeeper, Superintendent of Police Rajen Singh said.
Police found three empty AK-47 cartridges from the spot.
Tension prevails in Kokrajhar and its adjoining disticts in Lower Assam with protesters coming out on the streets. Volatile situation was also reported in some places along the National Highway 31.
Security in all the districts of Lower Assam has been intensified following the killing.
Assam Chief Minister Sarbananda Sonowal has condemned the incident and directed DGP Mukesh Sahay to review the prevailing situation.
A massive hunt has been launched to nab the killers and further investigations were on, police added.