Sadar union BNP unit chief Amirul Hossain Chakdar was arrested at his house on Tuesday night, Nasirnagar police OC Abu Zafar said on Wednesday.
At least 17 temples and more than 50 Hindu houses were vandalised and over 100 people were injured when a mob attacked Hindu-dominated neighbourhood in the upazila on Oct 30.
A defamatory Facebook post allegedly by a Hindu youth is said to have triggered the attack.
Six more houses were torched on Nov 4 and another on Sunday.
An investigation committee, formed by the police headquarters, submitted its findings on Monday.
It highlighted political rivalry in the area and estimated that around 20 people directly or indirectly instigated the attacks.
The ruling Awami League had suspended three of its Nasirnagar unit leaders for their involvement in the attacks on Hindus.