Russian authorities have arrested two people they claim were involved in the assassination of a senior naval officer, Captain 1st Rank Valery Trankovsky, in Sevastopol last week. The Federal Security Service (FSB) says the operation was orchestrated by Ukraine’s Security Service (SBU).

A Targeted Attack

Trankovsky, the deputy commander of the Azov branch of Russia’s Black Sea Fleet, was killed in a dramatic explosion as he headed to work. According to the FSB, a bomb was planted under...