Kazerun County’s Friday prayers leader Mohammad Khorsand was approached by the murderer in the early hours of Wednesday as he was leaving a religious ceremony together with his wife.
The attacker then asked the victim for a selfie photo shot before stabbing him and running away.
Khorsand later succumbed to his injuries at a hospital.
The attacker, however, was arrested at a park in the county, according to Colonel Kavous Mohammadi, the deputy for social affairs at Fars’ Law Enforcement Force.
A video by the country’s state TV show the moment the assailant is being arrested by the police.
Ahmad Ahmadi-Zadeh, an official with the Provincial Governor’s Office, also told the agency that an investigation was underway into the motive of the attacker, who has not yet been identified.
Last month, a theological pupil was gunned down by an assailant in the western province of Hamadan. The murderer was quickly identified by local security forces and was killed during an armed clash.