The incident took place at the home of Tejendra Sheel at Sheelpara of Dakkhin Sadhanpur of Banshkhali Upazila on the midnight of Nov 18 in 2003.
Bangladesh Hindu, Buddha, Christian Oikyo Parishad on Friday held a protest rally and a silent procession demanding punishment of those guilty.
Two surviving sons of Tejendra — Bimal Sheel and Nirmal Sheel — were also present at the rally that took place at Andarkilla.
Bimal filed a murder case following the killing.
Speakers at the rally expressed frustration over the delay in holding the trial process as well as the court's decision to grant bail to the accused.
Nirmal on Friday told bdnews24.com that police arrested 14 of the 31 accused, who admitted setting fire to the house as part of a plan hatched by BNP leader and Kalipur Union chairman Aminur Rahman Chowdhury.
He said seven of the 14 have recently secured bail and "they are now threatening us."
"We also objected to the final charge sheet which did not include the name of the mastermind Aminur Rahman Chowdhury."
The Criminal Investigation Department has submitted the witnesses' statements after investigation to the public prosecutor.
Nirmal demanded formation of a judicial probe commission, adding, "The present prime minister vowed to bring the culprits to justice but nothing has happened so far despite the fact that seven years have elapsed."