Intissar al-Hassaeri and her aunt were both found shot dead in the boot of a car in Libya on Tuesday
The body of a female civil society activist was found stuffed in the boot of a car in the Libyan capital on Tuesday, a security source said.
The corpse of Intissar al-Hassaeri was discovered in Tripoli along with that of her aunt "hours after their disappearance" on Monday night, the source told AFP.
"Both were shot dead," the source added.
Hassaeri, 35, was a founding member of the Tanweer cultural and social movement.
The rights activist had taken part in several gatherings last year protesting the presence of militant groups in the capital.
Since the 2011 overthrow of dictator Muammar Gaddafi in a NATO-backed uprising, Libya has been awash with weapons and opposing militias are battling for control of its cities and oil wealth.
It has rival parliaments and governments, one backed by Egypt, Gulf states and the West and the other, in Tripoli, aided by Islamist-supported militias and supported by Qatar and Turkey.
"This act clearly proves that Tripoli is not safe and is under the threat of terrorism," the Tobruk government said in a statement.
In June 2014, lawyer and human rights activist Salwa Bouguiguis was shot dead by unknown assailants in the second city of Benghazi, a month after a Libyan journalist was killed after she had criticised militant groups.