Muhammad Bilal Khan, having over 16,000 followers on Twitter, 48,000 on his YouTube channel and 22,000 on Facebook, was with his uncle Ehtesham, when he received a phone call after which a man took him to the nearby forest on Sunday night, Dawn news quoted police as saying.
Superintendent of Police Saddar Malik Naeem said Khan was attacked in the G-9/4 area of Islamabad and was shifted to a hospital where he succumbed to his injuries. His uncle was severely injured and has been hospitalised, he said.
The suspect used a dagger to kill him, Naeem said, adding that some people heard gunshot firing as well.
Apart from being a social media activist, Khan was also a freelance journalist.
He hailed from Gilgit-Baltistan and was a Shariah graduate from the International Islamic University of Islamabad (IIUI), according to Express News.
Soon after his killing, #Justice4MuhammadBilalKhan started trending on social media.
Several Twitter users said that his criticism of the Pakistan Army and the Inter-Services Intelligence (ISI) led to his killing.
"Pakistani activist and journalist Mohammad Bilal Khan was shot dead last night in Islamabad. Khan was known for his criticism of the all-powerful military and its notorious spy agency," a man said in a tweet.
The deceased's father Abdullah said that his body had marks of a sharp tool.
"My son's only fault was that he spoke about the Prophet," he said.
A case was registered under various sections including the Anti Terrorism Act.
The incident has created fear among people, Khan's father said.