Two unidentified visitors shot dead on Wednesday Pir Hisham al-Din, an attorney and aide to Sayid Ali Shah Gilani, inside his home at Bemina, a residential area on the outskirts of Kashmir's summer capital, Srinagar.
"They said they wanted him to attest a document, and when he came out to see the visitors, one of them took out his weapon and shot him in the head," family sources said.
A pan-Islamist by ideology, Hisham al-Din had joined the Jamaat-e-Islami on his return to Kashmir after studying law at Aligarh Muslim University, a famed centre of learning in north India.
He had been jailed several times by the Indian authorities for advocating Kashmir's secession from India and merger with neighbouring Pakistan.
"It is unbelievable," Sayyid Gilani said over phone from New Delhi, where he is undergoing treatment for a heart ailment.
"He believed in Islam being a complete way of life and played a vital role in the freedom struggle. Those inimical to this ideology have made him a martyr."
Of late, Hisham al-Din had been actively involved in the formation of a new political party, Tehrik-e-Hurriyat Jammu Kashmir, founded by Sayid Gilani last month after the latter parted ways with the more conciliatory leadership of the Hurriyat Conference, an amalgam of Kashmiri separatist parties.
Grieving family members testify
to continued strife in the valley
Gilani is regarded as a hawk within the Hurriyat Conference for his strenuous opposition to peace talks between the moderates and the Indian Government.
His pre-condition for any dialogue with New Delhi is that Pakistan be involved in the tripartite dialogue.
The Hurriyat Conference split last year on this and related issues.
"This seems to be a result of internal bickering," a senior Kashmir police officer said when asked who could be responsible for Hisham al-Din's killing.
Another police officer pointed out that, earlier this year, Moulvi Mushtaq Ahmad, uncle of Kashmir's chief Muslim priest and leader of a rival faction of the Hurriyat Conference Mirwaiz Umar Faruq, was murdered inside a Srinagar mosque.
"Hisham al-Din ... played a vital role in Kashmir's freedom struggle. Those inimical to this ideology have made him
Sayid Ali Shah Gilani, prominent Kashmir separatist leader
A little-known organisation, Save Kashmir Movement, later claimed responsibility of Mushtaq's killing.
In recent weeks a number of fighters from Kashmir's most prominent indigenous separatist group, Hizb al-Mujahidin, as well as fighters from groups dominated by foreign volunteers, have been killed in suspected factional feuds.
So far, no individual or group has claimed responsibility for Hisham al-Din's killing.
"We're investigating," Inspector-General of Kashmir Police K Rajendra Kumar said.
A spokesperson for Hizb al-Mujahidin has blamed "Indian agents" for Peer's murder.
In the 16 years since an armed rebellion broke out in Indian-administered Kashmir, more than 40,000 people have died according to official statistics, while local rights groups put the death toll at double that figure.
Civilians are frequently caught in
the middle of deadly firefights
Talks between India and Pakistan on Kashmir and other issues have been deadlocked for some time now.
Pakistan is reported be insisting on the inclusion of Kashmiri representatives in the talks, while India opposes the idea in line with its position that the Kashmir issue should be resolved through bilateral dialogue.