Witness accounts and official reports corroborate this.
They observed that nearly ten months after the incident, implicating and arresting a university teacher now appears both "motivated and deliberate".
The signatories highlighted discrepancies between the First Information Report (FIR) and published media reports, adding that the plaintiff of the case had told the media, "Police took my signature, but I do not know who has been accused."
They noted that Shamesh was buried without a post-mortem examination.
Under such circumstances, they said, implicating a university teacher raises serious questions about the impartiality of the judicial process and poses a threat to freedom of expression.
Mahmudul is a former member of the Jatiya Press Club, a former metro editor at The Daily Star, a former sub-editor at UNB, and an alumnus of the Department of Journalism at Rajshahi University.
"We consider this arrest an act of harassment. We urge the authorities to intervene for his immediate release, the withdrawal of the case, and a transparent, impartial, and judicial investigation into the incident," the statement said.
Among the signatories are Prof AA Mamun, Prof Md Mozammel Hossain Bakul, Shatil Siraj, Kazi Mamun Haider and Soma Deb of Rajshahi University; Mahfuz Mishu, special correspondent at Jamuna TV; Sushanta Sinha, special correspondent at Ekattor TV; Tasnim Humaida, teacher of Begum Rokeya University; Atikur Rahman, associate editor at Manabkantha; Enayet Karim, Rajshahi bureau chief of Khaborer Kagoj; Arafat Rahaman, staff reporter at The Daily Star; Md Mamun A Kaiyum, PhD researcher at Queensland University of Technology, Australia; Din Mohammad Shibli, principal at Chhaya Institute of Communication and Photography; Md Ferdous Mobarak, news editor at Times of Bangladesh; Rezaul Karim Shamim, associate editor at Kalbela; as well as more than three dozen other university teachers, journalists, researchers, public relations officers, bankers, and professionals from different fields.