The separatist insurgent Balochistan Liberation Army (BLA) released a statement saying it abducted and killed Lieutenant-Colonel Laeeq Baig Mirza, a rare attack on an officer of his rank in the region that borders Iran and Afghanistan.
Mirza was seized as he travelled back to the city of Quetta from Ziarat, a hill station, with his family and the friend on Tuesday night, a security official said.
"Around half a dozen militants blocked the Ziarat–Quetta Road some 22 to 25 km away from Ziarat (and) searched vehicles," the official told Reuters, asking not to be named as they were not authorised to talk to the media.
The gunmen took the officer and his friend, identified only as Umer, the official said.
The men's bodies were found in different locations in the mountainous Hernai district on Thursday morning, another official said.
The BLA and other separatist groups have been waging an insurgency for years in Balochistan, a resource-rich region which has attracted substantial Chinese investment.
In April a suicide attack killed three Chinese teachers in Karachi, the capital of neighbouring Sindh province, drawing strong condemnation from China.
The BLA claimed responsibility.
In February, insurgents armed with bombs and guns attacked two Pakistani military bases in Balochistan, killing seven soldiers and losing 13 of their own men.
