Deputy Chief Prosecutor of Dagestan’s capital, Makhachkala, was killed on Friday morning near his home.
Maksud Maksudov, who supervised the city’s penal institutions, was killed in the street as he was walking to his car.
Investigators believe he was shot at with Makarov pistol.
In a separate incident on Friday, one policeman was wounded in Dagestan city Kizil-Yurt in a militant attack.
The attackers fired several grenades from a launcher at a police detention station and fled in their car.
Meanwhile, Dagestan's police say they've also tracked down and killed four militants in a rural area near Cirtych village. Police sustained no casualties in the firefight.
In recent months, Russia's South has seen a surge in violence. In response, security forces launched a crackdown against the militants.