The suspect, Josip Grbesic, was arrested at his home on Friday after police investigators established that on October 10 he had fired a projectile from a rocket launcher on the mosque in Mostar's suburb Jasenica.
The attack occurred during the holy month of Ramadan, which caused great tension among local residents.
Police claim that after the attack, Grbesic left Bosnia-Herzegovina for Ploce in Croatia, where he was hiding in an apartment owned by his family. He returned to Mostar only on Friday, when he was arrested.
Local media claim that during the war in Bosnia Grbesic was a member of the Croatian Defence Council (HVO) Convicts' Battalion, which was under the command of Hague tribunal indictee Vinko Martinovic Stela.
Dnevni Avaz daily claims that Grbesic has a thick police record and that he admitted after his arrest that the attack was motivated by hatred towards Muslims.