A Pakistani journalist who was feared abducted after he went missing on Sunday has been found dead, his family has confirmed.
Police said Saleem Shahzad's body was found in a canal in Mandi Baha Uddin in Pakistan's northern Gujarat district.
Earlier, Human Rights Watch researcher Ali Dayan Hasan said he had "credible information" that Shahzad was in the custody of Pakistani intelligence.
He recently wrote an article about al-Qaeda infiltration in Pakistan's navy.
He reported that the militant group had launched the deadly assault on the Mehran base in Karachi, the headquarters of the navy's air wing, on 22 May because talks had failed over the release of several naval personnel arrested on suspicion of links to al-Qaeda affiliates.
At least 14 people were killed and two navy warplanes destroyed.
On Monday, a former navy commando and his brother were detained for their alleged role in helping plan the raid, which embarrassed the military.
Shahzad's family said he had disappeared after leaving his home in Islamabad on Sunday evening and heading to a television station to participate in a talkshow.
They immediately issued statements saying they feared for his safety.
The 40-year-old's body was found by local residents in a canal in the Sarai Alamgir area of Mandi Baha Uddin, some 150km (93 miles) south-east of the capital. His car was found about 10km (six miles) away.
The head of Margalla police station in Islamabad, Fayaz Tanoli, told the BBC that the local police force took photographs of the body and informed his officers on Monday that it might be Shahzad's.
The photographs were shown to Shahzad's brother-in-law, Hamza Amir, who identified the remains. Police said he had cuts to his face.
Relatives later travelled to Sarai Alamgir to confirm he was dead.
Mr Hasan of Human Rights Watch said Shahzad had recently complained about being threatened by the intelligence arm of the Pakistan military, the Inter Services Intelligence Directorate (ISI).
After writing one article in October, Shahzad was summoned to an ISI office, where an intelligence officer issued what appeared to be a veiled threat, he added. Shahzad sent him notes of the meeting "in case something happens to me or my family".
"The perpetrators of this murder have to be identified through a transparent inquiry and due process, and must be held accountable. However, Human Rights Watch is aware that Saleem Shahzad had claimed to have received multiple threats from the ISI, and we regard those threats as credible," Mr Hasan said in a statement.
"While it is yet to be determined who killed him, the manner of his killing is reminiscent of other incidents where there was credible intelligence of involvement by Pakistan intelligence services."
Mr Hasan said he had been told by some Pakistani government officials that they believed Shahzad was in ISI custody.
A senior Pakistani intelligence official told the Associated Press it was "absurd" to say that the ISI had anything to do with Shahzad's death.
The Pakistan Federal Union of Journalists said: "We are losing our professional colleagues but the government never unearths who is behind the killing of journalists."
Prime Minister Yousuf Raza Gilani has expressed his heartfelt condolences to Shahzad's family and ordered an immediate inquiry into his kidnapping and murder.
Shahzad, who had a wife and three children, worked for the Italian news agency Adnkronos International (AKI) and was Pakistan bureau chief for Asia Times Online.
Human rights groups recently called Pakistan the most dangerous place in the world for journalists to operate, saying they were under threat from Islamist militants but also Pakistan's military and intelligence agencies.