Azerbaijan’s Prosecutor General’s Office on Tuesday launched a criminal investigation into what it called the “cruel and deliberate murder” of two Azerbaijani citizens during a police raid in Russia, after autopsy results showed they died from severe injuries sustained in custody.

The victims, identified as brothers Ziyaddin Safarov, 55, and Huseyn Safarov, 60, were among 50 people arrested last Friday in the city of Yekaterinburg.

Russian investigators said six ethnic Azerbaijani men with Russian citizenship — four of them with the last name Safarov — were arrested as part of murder investigations dating back to the early 2000s. They claimed one man had died of a heart attack during the raid and that the second death remained under investigation.

The two Safarov brothers’ bodies were flown to Baku on Monday and examined later that night. Azerbaijani prosecutors said an autopsy showed they died from severe blood loss and shock due to extensive physical trauma, including broken ribs and internal injuries.

“A criminal investigation has been launched… concerning the torture and brutal killing of Azerbaijani citizens and individuals of Azerbaijani origin in the Russian Federation,” the Prosecutor General’s Office said in a statement.

“None of the brothers were killed with a sharp object or firearm. They were struck with a blunt object,” Azerbaijan’s chief medical examiner Adalat Hasanov told reporters.