A top human rights group is urging Pakistan's government to do more to find the killers of a Pakistani journalist who was investigating alleged links between the military and extremists.

A Pakistani commission investigating the murder of Saleem Shahzad said in a recent report that it lacked enough evidence to name those behind his killing. Shahzad had alleged that Pakistani intelligence agents were after him, an allegation dismissed by Inter-Services Intelligence , Pakistan's main spy agency.

An official with the U.S.-based group Human Rights Watch says the commission's inability to name those responsible for Shahzad's murder speaks to how the ISI remains beyond the reach of the country's criminal justice system.

Shahzad, who worked for the Hong Kong-based Asia Times Online, disappeared last May from Pakistan's capital, Islamabad. His body was found in a canal bearing signs of torture.

Shahzad had been looking into possible ties between Pakistan's military and Islamist militant groups.

Shahzad once reported that al-Qaida militants had attacked a Pakistani naval base after talks failed to secure the release of two naval officials arrested on suspicion of links to the global terror network.