The Balochistan-based journalist had been missing since 24 March. He was tortured to death.
His body was discovered on Wednesday alongside another mutilated body in Karachi’s Surjani Town area.
It is not clear who killed Mr Razzak. Pakistan is one of the world’s most dangerous countries for journalists.
It took Mr Razzak’s family 24 hours to identify him because only his arms and legs were sufficiently intact to enable identification.
“After kidnapping him, he was severely tortured to death,” his sister Saeeda Sarbazi told the BBC.
The BBC’s Ahmed Wali Mujeeb in Karachi says Mr Razzak worked for the daily Balochi-language newspaper Tawar where he was a senior sub-editor.
Reports say he was also linked to a Balochi political party.
“Journalists in Balochistan and the Tribal Areas are constantly the targets of intimidation and violence, and the impunity enjoyed by those who murder them just sustains this climate of terror,” Reporters without Borders said.
“The authorities must end it at once by pursuing this investigation to its conclusion.”
Six journalists have been killed in Pakistan this year, four of them Balochistan.
[Courtesy by: BBC News]