KARACHI: A key witness in the murder case of prominent rights activist and co-founder of social forum, The Second Floor (T2F), Sabeen Mahmud, was shot dead in a suspected targeted attack Monday evening, officials said.

Ghulam Abbas, a police constable, who used to work as a part-time driver for Ms Mahmud, was gunned down in Korangi area of the city. He was a key witness to the killing of Ms Mahmud in April 2015 – just after she had organised a seminar on Balochistan's missing persons at T2F.

Take a look: Director T2F Sabeen Mahmud shot dead in Karachi.

“The victim, Ghulam Abbas, was an important witness of the case and his murder underlines the urgency of protecting the remaining witnesses,” said Counter-Terrorism Department official Raja Umer Khattab.

Mr. Khattab was instrumental in arresting five accused who were also allegedly involved in killing over 40 members of the Shia Ismaili community near Safoora Goth, among other cases.

According to Mr. Khattab, Sabeen Mahmud's driver's murder was an act of targeted killing.

Khattab said Ghulam Abbass was sitting on the rear seat of the car when Sabeen Mahmud was attacked as she was driving herself.

The late Ghulam Abbas had identified the accused in the murder case before a magistrate, recalled the CTD official.

On Monday, Abbas was returning home after offering prayers when he was attacked by armed pillion riders; he sustained two bullet wounds fired from a 0.9mm pistol.

“Ghulam Abbas was an important witness in the Sabeen Mahmud murder case but his killing would not affect the case since the identification parade had already taken place,” opined the CTD official.

However, Mr. Khattab suggested that the murder underlined the importance of protecting the remaining witnesses in the case.