The arrestee was identified as Supriyo Saha Roy, 28, son of Sudhangshu Saha Roy of the upazila.
Md Majharul Karim, Officer-in-charge of Kalmakanda Police Station,
said Supriyo has been sharing anti-Muslim posts on face-book since April 18 which created agitation among the local Muslims.
He was arrested from his house on Tuesday night, OC said.
A case was filed against Supriyo under Digital Security Act.