Hundreds of mourners gathered in the Pakistani city of Karachi for the funeral of slain Saleem Shahzad - one of the country's most renowned investigative journalists.

On Tuesday, Shahzad's body was found with marks of torture in a canal after disappearing for two days.

Human Rights Watch says Shahzad told them that he was under threat before being abducted.

Imtiaz Tyab reports from Islamabad, Pakistan's capital.