Anjan Chakraborty was arrested from Khyndailad area of East Khasi Hills district last evening, Superintendent of Police Davis Marak told PTI.
He was produced in a court and West Bengal police have taken custody of Chakraborty who had served the state police as an inspector and had taken early retirement.
Police recovered two mobile phones, cash and a few fake identity cards from his possession, the SP said.
Chakraborty allegedly duped several people in Kolkata impersonating as the assistant commissioner of the detective department of Kolkata Police, a police officer here said.